by Michelle Marraffini, SERC marine biologistThe sun shimmers on the still waters of Monterey Bay, Calif., this beautiful October morning as we prepare for our dive survey. As we stand on the shore unloading our sampling gear, we can see the tops of giant kelp break the surface and an otter munching on a freshly caught crab. We’re about to dive into the Pacific Ocean in search of nonnative species on the outer coast.
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by Kristen Minogue
It’s no secret that River Herring are in trouble. There was a time, back in the 1950s, when Maryland fishermen regularly pulled in 4 million pounds or more a year of the silver fish. Then something mysterious happened. Herring harvests generally fluctuate from year to year. But in the 1970s, they fell and never came back up. For the last four decades, commercial fishermen in Maryland have been lucky to catch a few hundred thousand a year. Now they catch none.
Food doesn’t typically get the spotlight in talks on climate change. Even when human health enters the picture, heat waves and category 5 hurricanes often dominate coverage. But as the Earth changes, so does agriculture. That raised just one of several questions scientists wrestled with at the Smithsonian’s second climate change symposium, titled “Living in the Anthropocene”: What will the world’s 7 billion people eat?
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.
By Sarah Hansen
“Is the net like a Spongebob jellyfish net?” student Cristal Sandoval asked. Alison Cawood, citizen science coordinator at the Smithsonian Environmental Research Center (SERC), used another analogy to explain: “It’s like a bowl with holes in it for pasta.” Light bulbs came on around the room and a knowing, “Oh,” escaped the lips of at least a dozen students.
by Melissa Pastore, biology graduate student at Villanova University
What if we could create a giant sponge capable of soaking up nitrogen pollution? It turns out that the Chesapeake Bay, which has experienced a rapid increase in nitrogen pollution from municipal and agricultural sources over the last few decades, already contains a natural version of this sponge: marshes fringing the Bay. But global change—and the nitrogen pollution itself—could change how this natural sponge operates.
by Kristen Minogue
Every year, thousands of crab pots disappear, their lines snapped by violent storms or severed by the propellers of passing boats. Cut off from the buoys that once marked their presence, they become “ghost pots,” lost at the bottom of the Chesapeake.
But ghost pots aren’t dead pots. They’re still quite capable of trapping crabs, including mature females undergoing their spawning migration. And with no one to retrieve them, crabs too large to escape are condemned to a slow death by starvation. This often has the eerie effect of luring even more animals to their demise, says Laura Patrick, aquatic ecologist at the Smithsonian Environmental Research Center (SERC).
“The crabs are just going in and they’re dying,” Patrick says. “And one of the problems is that the dead animals that are in there can be bait for new crabs to come in. So it’s kind of a self-baiting pot.”
by Sarah Hansen
No one disputes that blue crab numbers in Chesapeake Bay are low. There is much discussion, however, about what to do to fix the problem. Smithsonian Environmental Research Center intern Julie Sepanik is working with SERC postdoctoral fellow Matt Ogburn to develop a computer model that will help improve our understanding of blue crab population dynamics in the Bay. The model works to identify where female crabs mature in the Bay and track their migration to lower Bay spawning areas. Ultimately, they hope the model will help inform decisions about preserving habitat and restoring the population.
By Sarah Hansen
At first encounter, the marsh looks as if it came out of a Heinlein novel. Boxy white robots dot the wetland, igloo-shaped encampments litter the landscape, and thick black tubes snake across the mud—wait, did that one just move? On closer inspection, clusters of human beings appear crouched in the sedge, carefully taking measurements for the annual Global Change Research Wetland (GCREW) Summer Marshfest.
“These two weeks are the most important two weeks of the year for us,” said Smithsonian Environmental Research Center biogeochemist Patrick Megonigal. During Marshfest, senior scientists, postdocs, volunteer citizen scientists, interns, lab techs and visiting students all join forces to collect data for three experiments focused on climate change and nutrient cycling, all managed by Megonigal. Click to continue »
by Kristen Minogue
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.