April 3, 2013
Think twice before you order earthworms to improve the soil of your garden. A group of scientists from the Smithsonian Environmental Research Center (SERC) and Johns Hopkins University’s Department of Earth and Planetary Sciences recently published a study that shows the damage non-native earthworms, who creep their way into forests thanks to human activities like fishing and gardening, may cause to one of the world’s favorite flowers, the orchid.
Of more than 20,000 orchid species, the study focused on Goodyera pubescens, a tall, erect plant with white flowers common in America’s east coast forests, including those around the SERC campus in Edgewater, Maryland. The problem with earthworms, the scientists found, is that they reduce Goodyera pubescens’ numbers by ingesting their seeds, which are the size of dust specks and fall into the soil surrounding orchids when the plants flowers. As earthworms munch through the dirt, they swallow the microscopic seeds, preventing germination in two ways: Either the ingestion process kills the seeds before they make it out the earthworm’s other end, or the seeds survive ingestion but are reintroduced into the soil too deeply to access upper-level fungi nutrients required for growth.
The research team, made up of Melissa McCormick, Kenneth Parker and Dennis Whigham at SERC and Katalin Szlavecz at Hopkins, measured the effect of both possibilities over six weeks. They determined almost 80 percent of the seeds ingested in this time period could no longer grow, and almost a third were buried too deeply to flourish. By a conservative estimate, the study concludes, older forests—120 to 150 years old—around SERC would lose 49 percent of Goodyera orchid seeds to earthworm ingestion in a year, and younger forests—50 to 70 years old, where non-native earthworms flourish—would lose 68 percent.
These numbers do not suggest that earthworms are inherently bad for orchids. On the contrary, native earthworms keep the plants’ ecosystems in balance, and allow plenty of room for growth. What the numbers do show, explains McCormick, is that the unchecked introduction and proliferation of new earthworm species in forests has a dramatic effect that defies the conventional wisdom that earthworms always are great for soil health.
“Certainly where earthworms belong, when they’re in their correct system, they have a really major role in how the forest functions,” McCormick says. “The problem is when you get different species in there that are functioning very differently. People need to be a little bit more aware of what species sort of belong here and which ones don’t, and just be aware that they’ve having effects other than just how well your garden is doing. Yes, it’s certainly great for your garden, but it’s got a cost.”
That cost may stretch far beyond orchids. As part of a forest ecosystem, orchids actually are relatively insignificant, McCormick says; they are beautiful, but don’t contribute much. Yet earthworms also might disrupt the distribution and diversity of the fungi on which the orchid seeds feed, she explains, which would have a much more fundamental effect on the forest, because many plants depend on them. Orchids in this case would be like canaries in coal mines.
“Orchids are a way of seeing the health of an ecosystem,” says McCormick. “They depend on this very complicated interlinked system, where they depend on things above ground and other species below ground as well, so it’s an indication that the ecosystem is pretty healthy when they’re there.”
When they aren’t there, she cautions, the loss of beautiful flowers may be the least of our concerns.
October 29, 2012
UPDATE, Tuesday, October 30, 2012: Museums and the National Zoo remain closed, but Metro rail and bus service will open at 2 on a limited Sunday schedule. All museums and the National Zoo will open tomorrow on time on their regular schedules.
UPDATE: The National Zoo has announced it will remain closed through Tuesday, October 30, due to conditions from hurricane Sandy. The Smithsonian museums also will remain closed in both Washington, D.C. and New York City. Metro rail has announced that all rail and bus service will be shut down also on Tuesday.
UPDATE: The Smithsonian Institution has announced that all museums and the National Zoo in both the Washington, D.C. area and in New York City will be closed tomorrow, Monday, October 29, due to Hurricane Sandy.
The following statement was just released: “In New York, the Smithsonian’s National Museum of the American Indian George Gustav Heye Center is closed, due to the impending storm. The Cooper Hewitt, National Design Museum continues to be closed for construction. The Smithsonian will provide further information if the storm affects the Washington, D.C. museums.”
In addition, the National Portrait Gallery reports that the 1812: Portraits of War Edgar P. Richardson Symposium, scheduled for tomorrow has also been cancelled.
With reports rolling in that the D.C. area might be headed for a collision with Hurricane Sandy, the Smithsonian is hard at work preparing for the weather. The Washington Post’s weather gang has been following the storm and reports that, “analyses suggest this storm may be unlike anything the region has ever experienced.” But don’t worry, the Smithsonian has it covered.
With so many adorable animals, including the two-week old dama gazelle who made her debut on Wednesday, the Zoo has a big task but one caretaker Juan Rodriguez says they are ready.
Rodriguez, who works with the pandas as well as other outdoor exhibits, says, “My area is a little bit more susceptible to damage than other areas, like the Elephant House and the Great Ape House. For the houses, everything’s all indoors, so they’re sheltered.” As the storm heads further north, Rodriguez says the team will keep an eye on the weather and assess the situation each morning.
“We’ll probably just leave them inside if the winds are above 50 miles an hour or so,” says Rodriguez, adding that, “If they’re near trees and a tree falls or a branch falls and breaks the fence line, some of those areas have no secondary containment, so we need to keep them inside.” Animals with indoor-outdoor access, like the fishing cats and clouded leopards, will likely have to stay inside if the weather takes a turn for the worse.
But Rodriguez says, the animals don’t tend to mind. “As long as they’re fed at the same time, they’re happy.” In fact, the toughest transition for the animals tends to be the time change in the spring that sets their eating schedules back an hour.
Up at the Smithsonian Environmental Research Center in Edgewater, Maryland, the staff are taking precautions for the weekend. With 2,650 acres of land to manage, SERC also has waterfront to manage. Press officer Kristen Minogue says they’ve been moving boats, including large research crafts off docks and out of the water for safekeeping. “On a brighter note,” says Minogue, “our nutrient lab said they’re looking forward to finally getting some rain because they’ll be able to take stream data again. Their nitrogen research has been on hold since the streams stopped flowing in the summer.”
Meanwhile, the Institution remains optimistic that the museums will be able to stay open. Last August, when Hurricane Irene threatened severe weather, the museums prepared with 1,000 sandbags to prevent flooding, backup produce and dry feeds for Zoo animals and plywood, metal and nylon bands to secure the Castle’s turrets and chimneys.
UPDATE: This post was updated on October 28 after the announcement was made to close all of the museums and the National Zoo for the impending storm.
September 14, 2012
Just a short drive to the east, the Smithsonian Environmental Research Center (SERC) sits surrounded by trees, wetland and water–a wilderness perfect for studying everything from climate change to earthworms. While most of us work indoors at desks, Smithsonian ecologists call the 2,650-acre campus along the Chesapeake Bay their office. This Saturday, visitors will have the chance to get up close and personal with the work those scientists do at the annual Family Fall Day.
“I was drawn to this research site because it’s among the world’s most thoroughly studied wetland ecosystems,” explains biogeochemist Pat Megonigal. “It offers a wealth of data and the infrastructure I need to conduct a range of experiments on global change.”
In addition to the local research on marine life in the bay, SERC also hosts scientists around the world, from Belize to Alaska. Topics range from tropical mangroves to microscopic parasites that turn male crabs into females. The center is also known for its ongoing research into climate change, including an ongoing study begun in 1987.
“The main features are our research labs,” says Karen McDonald, outreach coordinator for the center. “It’s kind of unique because people actually get to meet world-class researchers.”
Megonigal’s work will be presented at one of the five laboratory demonstrations on Saturday. The labs include a look at forest canopy, trace elements, biogeochemistry, North American orchids and aquatic bottom dwellers viewed through a remote-contol camera. And of course, everyone’s favorite boat, Richard Lee, will be offering hour-long tours along the water. With plenty of opportunities for hands-on learning, including crabbing and seining in the bay, there’s something for everyone.
“I always look forward to the diversity of activities,” says McDonald. “There’s always something different every time you come.”
Registration required, here. Saturday September 15, 10 a.m. to 2 p.m.
February 7, 2012
Our inquisitive readers are rising to the challenge we gave them last month. The questions are pouring in and we’re ready for more. Do you have any questions for our curators? Submit your questions here.
How much is the Hope Diamond worth? — Marjorie Mathews, Silver Spring, Maryland
That’s the most popular question we get, but we don’t really satisfy people by giving them a number. There are a number of answers, but the best one is that we honestly don’t know. It’s a little bit like Liz Taylor’s jewels being sold in December—all kinds of people guessed at what they would sell for, but everybody I know was way off. Only when those pieces were opened up to bidding at a public auction could you find out what their values were. When they were sold, then at least for that day and that night you could say, well, they were worth that much. The Hope Diamond is kind of the same way, but more so. There’s simply nothing else like it. So how do you put a value on the history, on the fact it’s been here on display for over 50 years and a few hundred million people have seen it, and on that fact it’s a rare blue diamond on top of everything else? You don’t. – Jeffrey E. Post, mineralogist, National Museum of Natural History
What’s the worst impact of ocean acidification so far?- Nancy Schaefer, Virginia Beach, Virginia
The impacts of ocean acidification are really just starting to be felt, but two big reports that came out in 2011 show that it could have very serious effects on coral reefs. These studies did not measure the warming effect of carbon dioxide in the atmosphere, but rather its effect of making the ocean more acidic when it dissolves in the ocean. Places where large amounts of carbon dioxide seep into the water from the sea floor provide a natural experiment and show us how ocean waters might look, say, 50 or 100 years from now. Both studies showed branching, lacy, delicate coral forms are likely to disappear, and with them that kind of three-dimensional complexity so many species depend on. Also, other species that build a stony skeleton or shell, such as oysters or mussels, are likely to be affected. This happens because acidification makes carbonate ions, which these species need for their skeletons, less abundant.
Nancy Knowlton, marine biologist
National Museum of Natural History
Art and artifacts from ancient South Pacific and Pacific Northwest tribes have similarities in form and function. Is it possible that early Hawaiians caught part of the Kuroshio Current of the North Pacific Gyre to end up along the northwest coast of America from northern California to Alaska? — April Amy Croan, Maple Valley, Washington
Those similarities have given rise to various theories, including trans-Pacific navigation, independent drifts of floating artifacts, inadvertent crossings by ships that have lost their rudders or rigging, or whales harpooned in one area that died or were captured in a distant place. Some connections are well-known, like feather garment fragments found in an archaeological site in Southeast Alaska that appear to have been brought there by whaling ships that had stopped in the Hawaiian Islands, a regular route for 19th-century whalers. Before the period of European contact, the greatest similarities are with the southwest Pacific, not Hawaii. The Kushiro current would have facilitated Asian coastal contacts with northwestern North America, but would not have helped Hawaiians. The problem of identification is one of context, form and dating. Most of the reported similarities are either out of their original context (which can’t be reconstructed), or their form is not specific enough to relate to another area’s style, or the date of creation cannot be established. To date there is no acceptable proof for South Pacific-Northwest Coast historical connections that predates the European whaling era, except for links that follow the coastal region of the North Pacific into Alaska.
William Fitzhugh, archeologist
Natural History Museum
August 26, 2011
Yesterday and today, our friends at the Smithsonian Environmental Research Center in Edgewater, Maryland, 25 miles east of Washington, D.C., have been busily preparing for the wrath of Hurricane Irene. The 2,800-acre research site is on the Rhode River, a sub-estuary of the Chesapeake Bay, where a storm surge of two to three feet is predicted.
According to Liza Hamill, SERC’s safety officer, boats are either being removed from the docks and hoisted up to safe areas on land or attached to a hurricane mooring, all loose equipment on site is being secured, sandbags are being placed around doors and rotating facilities teams are gearing up to monitor the center around the clock. All, as one might expect. But what threat does the storm surge pose to ongoing experiments there?
Well, for one, research biologist Mike Goodison had an important decision to make about a seawater pump that provides a constant flow of water from an area near the site’s docks to a wet lab 75 yards away, where tanks of live oysters, crabs and clams are held. The storm surge could destroy the seawater pump, but if he moved is somewhere safe, he would have to cut off that aspect of the experiments. Ultimately, he says, “It’s a $10,000 pump, so I can’t have it going underwater.” He will be removing the pump this afternoon and probably not reinstalling it until Monday.
So, what does that mean for the animals? “Normally, researchers keep their animals in tanks and the water constantly moves through, rather than being like a static fish tank,” says Goodison. “Basically people now, this morning, are going to have to start hoarding water and storing water to go with their animals. They are just going to have to turn their animal holding tanks into static systems until Monday.” Air pumps will continue to provide oxygenated water for the animals, as long as nothing happens to the backup power that is in place. “We have backup generators to supply power for everything at SERC. So if the power goes out, which we fully anticipate it will, then the backup generators will supply the electricity for some of the necessary infrastructure like the air pumps and keep the animals alive through the weekend,” says Goodison.
Luckily, the wet lab itself is about 20 feet above the water level, so it would have to be an incredibly high storm surge to cause damage or severe flooding to it.
About a mile across the water as the crow flies, or a 10-minute drive, from SERC’s main campus, is the Smithsonian Global Change Research Wetland, which is the site of four major experiments right now. The longest running of the experiments began nearly 25 years ago and is aimed at understanding the effects of elevated carbon dioxide in the atmosphere on plant communities. “The other three experiments all sort of build on that theme in order to make the experiments more and more realistic with respect to our forecast of the near future,” says Patrick Megonigal, an ecosystem ecologist and deputy director of SERC. One, for instance, looks at how elevated nitrogen levels in the water, in addition to raised carbon dioxide levels in the air, affects plants (essentially, simulating a polluted Chesapeake Bay). Another adds predicted sea level rise to those variables. And, another still, looks at how these global change factors will affect the ability for an invasive species called common reed to spread throughout native marshes.
For the experiments, open-top chambers, or plastic cylinders, that raise the carbon dioxide concentration around the plants to the level forecasted for 2100, are installed in the wetland. “Because the site is a tidal marsh, it is low in elevation, and it is right at the front lines for both storm surges. The stature of the plants is fairly low, which means the wind whips across it as well,” says Megonigal. “Our structures are hardy, but they are not built for hurricanes.” He and his colleagues have been dismantling parts of the chambers that might catch the wind and cause their destruction, and they are shutting down the carbon dioxide supply to the experiments. “We run it roughly from May through October,” he says. “Hopefully, it is a relatively small interruption.”
Megonical and his team are bringing in expensive instruments called infrared gas analyzers and raising other pieces of equipment above what they think might be the high water mark in the marsh.
“Prepare for the worst, and hope for the best,” says Hamill. That is the plan.