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Dead Zones Likely to Expand as Coastal Waters Warm

Monday, November 10th, 2014

by Kristen Minogue

Image: Menhaden fish kill in Narragansett Bay, Rhode Island. (Credit: Chris Deacutis)

Menhaden fish kill in Narragansett Bay, Rhode Island. (Chris Deacutis)

A full 94 percent of the world’s dead zones lie in regions expected to warm at least 2 degrees Celsius by the century’s end according to a new report from the Smithsonian Tropical Research Institute and the Smithsonian Environmental Research Center published Nov. 10 in Global Change Biology. The paper states that warmer waters—mixed with other climate change factors—make for a dangerous cocktail that can expand dead zones.

Dead zones form in waters where oxygen plummets to levels too low for fish, crabs or other animals to survive. In deeper waters, dead zones may last for months, as with the annual summer dead zone in the Chesapeake Bay. Temporary dead zones may occur in shallow waters at night. The largest dead zones in the Gulf of Mexico and Baltic Sea can cover more than 20,000 square miles of the sea floor. The number of dead zones across the world is growing exponentially, doubling each decade since the 1960s.

“They’re having a big impact on life in the coastal zone worldwide,” said Keryn Gedan, a co-author and marine ecologist at the Smithsonian Environmental Research Center and the University of Maryland. “A lot of people live on the coast, and they’re experiencing more fish kills and more harmful algal blooms. These are effects of dead zones that have an impact on our lives.”

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Oysters and the Chesapeake’s Jellyfish Wars

Tuesday, September 30th, 2014

Image: Jellyfish Chrysaora quinquecirrha (Credit: Lori Davias)

Jellyfish Chrysaora quinquecirrha (Lori Davias)

by Kristen Minogue

Every summer, the food web in Chesapeake Bay gets jostled around as two plankton-eating predators jockey for power: comb jellies and jellyfish. Most smaller species don’t have a stake in the battle—both predators eat zooplankton and fish eggs, after all. But for young oyster larvae, the victor could make the difference between being protected civilians or collateral damage.

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Why 900 Years of Ancient Oysters Went Missing

Friday, August 29th, 2014

by Kristen Minogue

Piscataway Indians lived on the Rhode River up to colonial times, though anthropologists believe they used the land for temporary campsites, not permanent settlements.

Piscataway Indians lived on the Rhode River up to colonial times, though anthropologists believe they used the land for temporary campsites, not permanent settlements.

For more than 10,000 years, Native Americans hunted and fished in the Chesapeake. Broken pottery, village sites, burial grounds and other artifacts bear witness to their near-continuous presence around the Bay. But one type of artifact—ancient trash piles called shell middens—hasn’t received as much attention. And these tell another important story.

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SERC camps cultivate environmentally-conscious kids

Tuesday, July 29th, 2014

By Sarah Hansen

"Who's been seining before?" asks Anna Youngk, SERC education intern and camp counselor.

“Who’s been seining before?” asks SERC education intern Anna Youngk (right).

“Hurry, hurry, hurry!  Baby pipefish!” camper Jack Yee, 11, squeals as he trundles across the beach in much-too-big waders with hands cupped.  A moment later the startled fish, caught by campers in a seine net, is swimming safely in a plastic tub already populated with silversides, glass shrimp, and one large pickerel.

XXXX (left) and Jack Yee are ready to dissect a perch.

Orion Ford, 10 (left), and Jack Yee, 11, are ready to dissect a perch.

Jack’s energy and concern for the creatures of Chesapeake Bay are exactly what SERC summer day camps are all about.  The programs range from “Pollywogs” camp for prekindergarten students to this week’s offering, “Environmental Detectives” camp for rising fifth- and sixth-graders.  Led by Education Department interns Anna Youngk, Lizzie DeRycke and Eric Glass, each week 12 children experience activities related to the Bay, its inhabitants, and what they can do to help. Click to continue »

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. (Chris Judy)

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 »

Blue Crabs Need (More Than) A Few Good Men

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

Chester_river_queen_annes_co_md

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 »