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Oysters have sidekick in Chesapeake Bay clean-up

Friday, July 25th, 2014

By Sarah Hansen

Keryn Gedan collects mussels and oysters "by the handful" for her research. (Keryn Gedan)

Keryn Gedan collects mussels and oysters “by the handful” for her research. (Keryn Gedan)

Oyster restoration has long been championed as key to cleaning up Chesapeake Bay, because oysters’ filter-feeding lifestyle improves water quality by removing plankton.  But oysters aren’t the only ones that can do the job.  A new study reports that another bivalve, the hooked mussel, also removes its share of plankton from the clogged Bay. Click to continue »

With Too Few Males, Blue Crab Reproduction
at Risk

Thursday, July 24th, 2014

by Kristen Minogue

Photo: Male blue crabs can mate with multiple females. But with fewer men to go around, their female partners are left with less sperm to reproduce. (Credit: SERC)

Male blue crabs can mate with multiple females. But with fewer men to go around, their female partners are left with less sperm to reproduce. (SERC)

The practice of selectively fishing male blue crabs in the Chesapeake—intended to give females a chance to reproduce—may have a hidden cost. A Bay without enough males could reduce the number of offspring females produce, ecologists at the Smithsonian Environmental Research Center found in a paper published in the July issue of Marine Ecology Progress Series.

Maryland and Virginia began reducing the harvest of female crabs by commercial and recreational watermen in 2008, the year officials declared the blue crab fishery a federal disaster. Since then, the crabs have shown signs of a shaky recovery. But a lasting comeback hinges on females producing enough offspring to sustain the population.

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SERC and NOAA model Bay’s murky water quality

Thursday, July 3rd, 2014

By Sarah Hansen

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Shelby Paschal, SERC intern, takes the “Secchi depth,” a measure of water clarity, while balancing on the fish weir.

In the Chesapeake Bay region, water quality is a big deal.  It can affect populations of economically important animals such as crabs and oysters, or shift ecological relationships among other species.  Differences in water quality might even determine whether an invasive species can establish a foothold in the Bay.

But water quality is a nebulous thing.  Even collecting water samples can be tricky, something intern Shelby Paschal knows first-hand.

“This is our obstacle course training,” Paschal says with a laugh, after a climbing onto a rickety fish weir at the Smithsonian Environmental Research Center (SERC).  Paschal and the rest of the Nutrient Lab, headed by senior scientist Tom Jordan, are running one piece of an ambitious 6-year project studying the effects of multiple factors in shallow near-shore habitats.  These critical habitats for small fish, crabs, and plants face threats from invasive species and construction, as well as from degradation of water quality caused by release of excessive nutrients from cropland into the Bay. Click to continue »

How much could streamside forests reduce nitrogen pollution in the Bay?

Monday, June 23rd, 2014

by Sarah Hansen

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A buffer on the Chester River in Queen Anne’s County, MD protects the river from nitrogen pollution. (USDA)

Nitrogen pollution in the Chesapeake Bay became a serious concern in the mid-20th century after the advent of nitrogen-rich chemical fertilizers. Bay restoration efforts have reduced nitrogen pollution somewhat, but achieving healthy nitrogen levels in the Bay is still a long way off. Croplands remain an important source of the nitrogen that pollutes Chesapeake Bay.

Don Weller, senior scientist at the Smithsonian Environmental Research Center, and his colleague Matthew Baker, associate professor of geography and environmental systems at the University of Maryland, Baltimore County, report in a new study that just over half the nitrogen from croplands might never reach the Bay—if all crop fields were protected by streamside forests and wetlands.

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Seeking Life in the Mud

Friday, June 13th, 2014

By Sarah Hansen

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Dean Janiak (left) and Ben Rubinoff collect a sample from the Rhode River.

Most of us think of the Chesapeake Bay as a single entity – one big body of water.  But Smithsonian Environmental Research Center (SERC) ecologist Dean Janiak and his intern, Ben Rubinoff, have a more nuanced perspective.  They’ve collected more than 150 samples from eight different habitats within the Bay and along its shoreline that contain mud, sand and lots of tiny animals.

Their ultimate goal: Discover how differences in habitats in the Rhode River (a sub-estuary of the Chesapeake Bay) can change biodiversity among creatures at the bottom of the river, and how those patterns change over time.  If it turns out that some habitats host more diverse animal communities than others, land managers can focus conservation efforts on those areas. Click to continue »

Invasive plant may protect forests from drowning

Thursday, June 12th, 2014

Citizen scientists brave dense swamps to find truth behind Phrag

By Sarah Hansen

JH bands a tree

Jack Hays bands a tree in the marsh.

Sea-level rise triggered by climate change affects coastal ecosystems first.  Marshes and wetlands along the shoreline creep inland, infringing on forest habitats.  Scientists have strong evidence that too much water will gradually drown the trees.  But an invasive reedy plant, known as “Phrag” from its scientific name, Phragmites australis, might be the forests’ unlikely protector, delaying drowning by about a decade.

Invasive Phrag (there is a native subspecies, as well) first came to the U.S. from Europe over 200 years ago.  The native variety coexists peacefully with other plants, but the invader takes over a habitat, choking off other flora.  Only recently, however, has its population growth exploded.   Scientists at the Smithsonian Environmental Research Center are trying to find out whether large Phrag populations in wetlands help or hurt tree growth.  It might seem counterintuitive, but scientists hypothesize that the Phrag is actually helping trees survive as sea level rises.  By removing some of the water, Phrag may prevent trees from drowning.     Click to continue »

The Strange, Controversial Way Plants Trap CO2

Wednesday, June 11th, 2014

by Kristen Minogue

Swamp Rose Mallow surrounded by blades of Schoenoplectus, a sedge in Drake's marsh experiment. (SERC)

Swamp Rose Mallow with blades of Schoenoplectus americanus, a sedge in Drake’s marsh experiment. (SERC)

Plants are among the world’s best carbon sinks, but there’s a side to the plant-CO2 love affair that’s rarely discussed. When carbon dioxide rises, plants cling to it more, releasing less back into the air—and until recently, scientists couldn’t figure out why. With a new paper published June 11 in Global Change Biology, ecologist Bert Drake believes he finally has the answer.

The process is called respiration, and it’s one of the most overlooked parts of the carbon cycle. Unlike photosynthesis, in which plants absorb carbon dioxide and release oxygen, respiration reverses it. And plants respire constantly. Much of the CO2 plants take from the atmosphere for photosynthesis finds its way back via respiration from plants and soil. Which leaves a major question: How much carbon can the world’s ecosystems store as CO2 rises and climate changes?

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Learning by Digging: Archeology Project Explores Colonial Life

Tuesday, June 10th, 2014

Scientists, students, and volunteers unearth late 17th- and 18th-century objects behind Sellman House

by Sarah Hansen

Volunteers excavate a new pit at the “Shaw’s Folly” site behind Sellman House.

On a sunny June afternoon at the Smithsonian Environmental Research Center, students and volunteers are hard at work in a cornfield behind the Sellman House.  Some shovel soil out of pits.  Others screen it with giant sieves, looking for artifacts.  Still others use trowels to smooth the bottom and sides of the pit, hoping to reveal differences in soil coloration and texture.  This scene will repeat every Monday, Tuesday, and Friday from about 9a.m. to 4 p.m. until June 20.  Guided by Laura Cripps, acting Chair of Social and Cultural Sciences at Howard Community College, and Jim Gibb, head of SERC’s Archaeology Lab, the group is excavating a site that contains objects and building materials that provide a window into 17th- and 18th-century life.

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Arctic Unguarded: Melting Ice Opens Way
for Invaders

Wednesday, May 28th, 2014

by Kristen Minogue

Arctic sea ice (Patrick Kelley/U.S. Coast Guard)

Arctic sea ice (Patrick Kelley/U.S. Coast Guard)


For the first time in roughly 2 million years, melting Arctic sea ice is connecting the north Pacific and north Atlantic oceans. The new sea routes leave both coasts and Arctic waters vulnerable to a large wave of invasive species—a problem the Arctic has largely avoided until now.

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What’s Hurting the Chesapeake’s Underwater Plants?

Monday, May 5th, 2014

by Kristen Minogue

Photo: A flounder in a bed of eelgrass. (NOAA)

A flounder in a bed of eelgrass. Seagrasses and other underwater plants provide food and shelter to many iconic Bay creatures, including blue crabs. (NOAA)

It’s been a difficult century for the submerged flora of Chesapeake Bay.

In the 1930s, wasting disease nearly wiped out the eelgrasses of the North Atlantic. In the ‘50s and ‘60s, they faced onslaughts from invasive grasses like water chestnut and Eurasian milfoil. Finally, in the summer of 1972, Hurricane Agnes pummeled underwater plants to the lowest levels ever reported in the Bay. This April, they received news that, at first glance, seemed positive: Submerged grasses rose 24 percent between 2012 and 2013, according to aerial surveys of the Chesapeake Bay Program.

But those increases were largely limited to a single species: widgeon grass, a plant known for wild fluctuations. At 60,000 acres total, submerged plants still didn’t come near a recent mini-peak in 2002, they’re a far cry from the ultimate goal of 185,000 acres across the Bay. What is holding them back? And—more importantly—how we can we help ensure the latest expansion isn’t just a blip?

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