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Invasive Species

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Wanted: The Hunt for Chinese Mitten Crabs Is Back On

Tuesday, May 15th, 2018
Chinese mitten crab held in outstretched hand

A Chinese mitten crab found in Chesapeake Beach, Md., in 2007. Chinese mitten crabs are most recognizable by their brown, spiny shells and furry “mittened” claws. (Credit: SERC)

by Kristen Minogue

An army of invading crabs has disappeared. But scientists are skeptical about whether they’re gone for good, or just hiding. As warmer temps lure people onto the water, Smithsonian scientists are asking boaters to report any sightings of the elusive Chinese mitten crab.

In 1992, a team of fishermen unexpectedly caught a Chinese mitten crab while trawling for shrimp in southern San Francisco Bay. From there, sightings of the brown, furry-clawed crustaceans exploded. In 1998, nearly three quarters of a million appeared in the North Bay alone. The mitten crabs threatened to collapse river banks with their burrows and made fishing nearly impossible in some places, as they clogged gear, stole bait or ate trapped fish.

“It was spectacularly abundant. A true outbreak,” said Greg Ruiz, a biologist with the Smithsonian Environmental Research Center (SERC). “And it clogged the water intakes. Water is the economy in California.”

Mitten crab numbers remained high through 2005. And then they vanished. Chinese mitten crabs haven’t been seen in California since 2010. Click to continue »

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Invader ID: Help Spot Invaders With Your Smart Phone

Wednesday, March 21st, 2018

by Kristen Minogue

Woman on docks holding plate with marine life, similar to the plates seen on Invader ID

SERC marine biologist Brianna Tracy holds a plate with marine life pulled from a dock in San Francisco. (Photo: Kristen Minogue/SERC)

Strange things grow on the bottoms of docks: brightly colored sponges, mat-like tunicates, and wispy, flower-shaped anemones. Many of these mysterious life forms are invasive species. This spring, Smithsonian marine biologists launched Invader ID, an online citizen science project calling on anyone with an Internet connection to help detect them.

The project centers on San Francisco Bay. With over 200 non-native species, it’s the most invaded estuary in North America. “The majority of the species that we identify in the San Francisco Bay are invasive,” said Brianna Tracy, a biologist with the Smithsonian Environmental Research Center. Click to continue »

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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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Bering Sea Days: Teaching Science
on the Last Frontier

Tuesday, December 5th, 2017

by Linda McCann, SERC biologist

The teachers on Alaska’s Pribilof Islands have a tradition. Every year for the last decade, they have invited scientists, educators and innovators from across the U.S. to take over their school for a week. The festival is known as Bering Sea Days. This year, marine biologist Linda McCann of the Smithsonian Environmental Research Center joined a team of 22 scientists and educators, leading games and activities to teach the community about the research being done on the unique animals and environment of the Bering Sea. Read the first-hand narrative below for a glimpse inside this remote Alaskan community.

Hiking through grassland

Students and educators hike through the rugged landscape of Alaska’s St. Paul Island. (Credit: Linda McCann)

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Tsunami Enabled Hundreds of Species to Raft Across Pacific

Thursday, September 28th, 2017

Biologists Detect Longest Transoceanic Rafting Voyage for Coastal Species

by Kristen Minogue

Barnacle-coated boat with Japanese characters washed up on beach

A Japanese tsunami vessel washed ashore in Oregon, coated in gooseneck barnacles. In a new study, scientists detected 289 species that rafted from Japan to the U.S. on tsunami debris, and they suspect many more were undetected. (Credit: John Chapman)

The 2011 Japanese tsunami set the stage for something unprecedented. For the first time in recorded history, scientists have detected entire communities of coastal species crossing the ocean by floating on makeshift rafts. Nearly 300 species have appeared on the shores of Hawaii and the U.S. West Coast attached to tsunami debris, marine biologists from the Smithsonian Environmental Research Center, Williams College and other institutions reported in the journal Science on Thursday.

The tsunami formed March 11, 2011, triggered by an earthquake of 9.0 moment magnitude that struck Japan the same day. When it reached the shore, the tsunami towered 125 feet (38.38 meters) over Japan’s Tōhoku coast and swept millions of objects out to sea, from small pieces of plastic to fishing boats and docks. These kinds of objects, scientists said, helped the species attached to them complete the transoceanic journey.

“I didn’t think that most of these coastal organisms could survive at sea for long periods of time,” said Greg Ruiz, a co-author and marine biologist at the Smithsonian Environmental Research Center. “But in many ways they just haven’t had much opportunity in the past. Now, plastic can combine with tsunami and storm events to create that opportunity on a large scale.”

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Q&A: Sherman’s Lagoon Cartoonist Jim Toomey on Ocean Conservation with Comics

Tuesday, September 12th, 2017

by Kristen Minogue

Artist with cartoon shark and cartoon sea turtle looking over his shoulder

Cartoonist Jim Toomey with two of his characters, Sherman the shark and Fillmore the sea turtle. (Image courtesy of Jim Toomey)

Since 1997, a great white shark named Sherman has put a wacky spin on life underwater in the comic strip Sherman’s Lagoon. Jim Toomey, the comic’s creator and conservationist, uses Sherman and his (usually more intelligent) friends to reveal real issues facing the ocean. In this Q&A, Toomey describes adding humor to environmentalism, and what happens when Sherman’s Lagoon meets Chesapeake Bay. Edited for brevity and clarity.

Want to dive deeper? Watch Jim Toomey’s TED Talk online. You can also meet Toomey at the Smithsonian Environmental Research Center October 17 at 7pm, for his free evening lecture, “Drawing Inspiration from the Sea.” Details here.

What first sparked your interest in the sea?

I was a little boy, maybe six, seven, eight years old….Some of the TV shows I used to watch, the Jacques Cousteau specials and things were somewhat unique. And it just fascinated me. It really captured my imagination to see this team of scientists explore this completely alien world. Click to continue »

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Tidings from the Sunset Coast (3)

Thursday, August 3rd, 2017

Countin’ Crabs at Seadrift Lagoon

by Ryan Greene, science writing intern

Green crabs piled on top of one another.

European green crabs (Carcinus maenas) caught in Seadrift Lagoon (Stinson Beach, Calif.). Credit: Ryan Greene/SERC

The Smithsonian Environmental Research Center’s (SERC) largest west coast outpost, SERC-West, sits on San Francisco Bay in Tiburon, California. SERC’s main campus is 2,000+ miles away on the Chesapeake Bay in Maryland. In an attempt to bridge this distance, we’ve launched Tidings From the Sunset Coast,” a summer series highlighting the work at SERC-West. Our most recent story was a spotlight of our summer interns. This post is about the invasive European green crabs in Seadrift Lagoon, just north of San Francisco. Enjoy!

How many crabs are in the lagoon? This question may sound like the middle-school carnival contest of how many jelly beans are in the jar. But for ecologists at SERC-West, it’s no guessing game—the health of an ecosystem hinges on the answer.

A view across water with houses, a mountain, and hanging mist.

Seadrift Lagoon is about 20 miles north of San Francisco Bay, and it’s said to have the highest density of European green crabs on the West Coast. Credit: Ryan Greene/SERC

Since 2009, Smithsonian scientists have partnered with the University of California, Davis, and Portland State University to tackle a two-clawed problem in Seadrift Lagoon: Carcinus maenas, the invasive European green crab. Seadrift is a small subdivision surrounding an artificial lagoon that sits smack between the Pacific Ocean and Bolinas Lagoon at the northern tip of California’s Stinson Beach. In the early 1990s, green crabs began to take up residence here, and since then they’ve done their fair share of damage.

The primary problems with green crabs in Seadrift are that they’re hungry and there are scads of them. This lagoon houses the highest density of green crabs documented on the West Coast, and they eat a whole lot. In nearby sites, like Tomales Bay and Bodega Bay, green crabs have caused native bivalve populations to plummet, and in some cases they have edged out other native crabs. In Seadrift, the sheer number of green crabs suggests that the impact on the ecosystem may be similarly drastic. That’s why in 2009, scientists at SERC-West, UC Davis, and Portland State started working with community members and citizen science volunteers to remove the crabs from the lagoon. Click to continue »

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Want Biodiversity? Love Your Enemies…Sometimes

Tuesday, August 1st, 2017

by Kristen Minogue

Three separate images of leaf infected by anthracnose, acorn with an insect hole and emerald ash borer.

Signs of three temperate forest enemies, left to right: Anthracnose (SERC), insect hole in an acorn (Jonathan Myers), emerald ash borer (Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org)

Walk through a forest in Maryland or Missouri, and you’ll probably find yourself surrounded by dozens of different tree species. Walk through a tropical forest in Brazil or Malaysia, and you’ll be surrounded by hundreds—in some forests, over 1,000. What’s behind this colossal difference in diversity? Scientists with the Smithsonian-led ForestGEO network came up with one morbid possibility: It may come down to having the right kind of enemy.

Earlier this summer, in a study in Science, researchers from 24 plots in the forest network from five continents pooled their data and detected a strange pattern: There’s a force at work in the tropics helping rare species thrive, a force that is much weaker in the cooler temperate zone.

Call it a clustering effect. The scientific term is “conspecific negative density dependence,” but it boils down to this: If too many trees of the same species grow in the same spot, they become magnets for enemies that slash their populations. In tropical forests, enemies generally knock them down just enough for new species to fill the gaps, without completely wiping out the first species. The result is a kaleidoscope forest with hundreds of species, many quite rare.

It may seem like a counterintuitive idea, that a lethal enemy could help sustain biodiversity. It can work when this thinning process prevents any one species from dominating.

“Just when a population is ready to take over, it catches a cold,” explained Sean McMahon, a co-author and forest ecologist with the Smithsonian Environmental Research Center (SERC). “And so it gets knocked back.”

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Tidings from the Sunset Coast (2)

Tuesday, July 25th, 2017

SERC-West Summer Intern Spotlights

by Ryan Greene, science writing intern

An intern in orange waders sprays a net hanging off the back of a boat.

Intern Elena Huynh helps clean a net during SERC’s annual zooplankton survey in San Francisco Bay. Credit: Ryan Greene/SERC

The Smithsonian Environmental Research Center’s (SERC) main campus is on the Chesapeake Bay in Maryland. SERC’s largest West Coast outpost, SERC-West, sits on the San Francisco Bay in California. To highlight SERC’s work out west, we’ve started Tidings from the Sunset Coast, a summer series about the life and times of SERC-West. Our first post explored California’s wet winter. This post features the stellar interns who are spending their summer at SERC-West.

Interns at the Smithsonian Environmental Research Center have the chance to work on independent projects while receiving personalized mentorship in a multidisciplinary atmosphere. Some people conduct experiments, others develop educational programs, and others (like me) write about the happenings at SERC. Simply put, SERC internships let you grow in whatever ways you want to be growing!

Check out the spotlights below to see what the interns at SERC-West are up to this summer. Click to continue »

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Tidings from the Sunset Coast (1)

Wednesday, July 12th, 2017

How California’s Record-Setting Rains Are Reshaping the Ecology of San Francisco Bay

By Ryan Greene, science writing intern

Clouds hang over the San Francisco skyline.

The San Francisco skyline as seen from San Francisco Bay. Credit: Ryan Greene/SERC

The Smithsonian Environmental Research Center’s (SERC) largest West Coast outpost sits on San Francisco Bay in Tiburon, California. The Tiburon branch, affectionately known as SERC-West, serves as the nexus of SERC’s research activities on the western coast of North America. At a whopping 2,462 miles from SERC’s main campus on the Chesapeake Bay in Maryland, SERC-West can feel a bit remote. In an attempt to bridge this distance, we’re launching Tidings From the Sunset Coast,” a summer story series about all things SERC-West. The first snippet is a story about the wildly wet winter California experienced this year and what all this fresh water means for the marine life in San Francisco Bay. Enjoy!

A big band of clouds stretches from Hawaii to the western coast of North America.

Image from NASA’s VIIRS satellite show one of many “atmospheric rivers” which slammed the California coast this past winter. Credit: Jesse Allen and Joshua Stevens/NASA Earth Observatory

When it comes to rain in California, the last few years have been a feast-or-famine affair. After a bitter drought that sported some of the driest years on record, this past winter brought more precipitation than the northern parts of the state have ever documented. To put it lightly, the weather has been extreme. And while the wet winter has refilled reservoirs and beefed up the snowpack, leading Governor Jerry Brown to end the drought state of emergency in all but four counties, it has also wreaked its fair share of havoc.

Here at SERC-West, scientists have been following another part of this story: the bombardment of freshwater runoff that inundated San Francisco Bay this winter. All the fresh water from the rain drastically reduced the saltiness (a.k.a. salinity) of the Bay. For many plants and animals used to saltier water, this was simply too much to handle. The devastation has been widespread, and according to ecologist Andy Chang, who currently heads up SERC-West, in some areas, the changes to the ecosystem might be less than fleeting.

“We’re kind of expecting to see local extinctions of some species that were here before,” he says. Click to continue »

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