Articles on this Page
- 06/24/15--09:22: _Oasis in the city
- 07/08/15--10:18: _Smithsonian and Par...
- 07/15/15--11:41: _A Precocious Black ...
- 07/21/15--07:52: _Kickstarter funding...
- 08/03/15--07:30: _CASSIOPEIA’S HIDDEN...
- 09/10/15--04:42: _Smithsonian Enlists...
- 10/08/15--06:01: _Colorful Caterpilla...
- 10/15/15--05:31: _Climbing plants dis...
- 10/29/15--04:53: _Nano Bible donated ...
- 12/02/15--09:42: _Smithsonian lab rec...
- 12/22/15--05:37: _Research shows same...
- 12/23/15--13:48: _The Power of Touch:...
- 01/07/16--12:20: _Trees employ simila...
- 01/19/16--12:26: _Elusive bush dog wi...
- 02/16/16--10:58: _Invasive Cobia Spre...
- 02/22/16--08:39: _‘The Wrong Wrights’...
- 03/18/16--05:06: _Sun-like Star Shows...
- 04/07/16--09:01: _Discovery: trap-jaw...
- 04/13/16--08:51: _25 Scimitar-Horned ...
- 04/22/16--11:01: _First North America...
- 04/28/16--07:45: _When is a blue bird...
- 05/10/16--11:46: _Red pandas come bac...
- 05/20/16--05:41: _Planet 9: A world t...
- 05/23/16--12:05: _Ancient Native-Amer...
- 06/01/16--08:48: _Endangered Kiwi Chi...
- 06/24/15--09:22: Oasis in the city
- Make sure that the garden offers a host source and a pollen source. There would be no butterflies or beetles to pollinate the different flowering plants if there are no caterpillars or larvae first. Make sure that the larvae or caterpillars’ essential food sources (for example, milkweed for monarch caterpillars) are available.
- Plant a variety of plants with differing flower shapes, colors, and bloom times to attract a diverse group of pollinators. Different pollinators have different methods of pollination. A variety of plants helps to give that pollinator the opportunity to find the plant that works best for them.
- Planting native species for that area in the garden is one of the most efficient and sustainable ways to support your local pollinators.
- 07/08/15--10:18: Smithsonian and Partners To Preserve Earth’s Genomic Plant Diversity
- 07/15/15--11:41: A Precocious Black Hole
- 07/21/15--07:52: Kickstarter funding: Neil Armstrong’s Apollo 11 spacesuit
- 08/03/15--07:30: CASSIOPEIA’S HIDDEN GEM: THE CLOSEST ROCKY, TRANSITING PLANET
- 10/08/15--06:01: Colorful Caterpillar Chemists
- 10/15/15--05:31: Climbing plants disturb carbon storage in tropical forests
- 10/29/15--04:53: Nano Bible donated to Smithsonian
- 12/02/15--09:42: Smithsonian lab receives GreenGov Presidential Award
- 12/22/15--05:37: Research shows same growth rate for farming, non-farming societies
- 12/23/15--13:48: The Power of Touch: Sex-changing snails switch sooner when together
- 01/07/16--12:20: Trees employ similar strategies to outcompete their neighbors
- 01/19/16--12:26: Elusive bush dog widespread in Panama
- 02/16/16--10:58: Invasive Cobia Spreads in Panama
- 02/22/16--08:39: ‘The Wrong Wrights’: A Graphic Novel from Smithsonian Books
- 04/13/16--08:51: 25 Scimitar-Horned Oryx to be Reintroduced to the Wild in Chad
- 04/22/16--11:01: First North American Monkey Fossils Found in Panama Canal Excavation
- 04/28/16--07:45: When is a blue bird not Blue?
- 05/10/16--11:46: Red pandas come back to Zoo
- 05/20/16--05:41: Planet 9: A world that should not exist
- Water depth and technology restricted Native Americans’ harvest primarily close to shore
- Oysters may have been harvested intensively at particular times of year and less so at others
- The density of the human population was drastically lower than today
- Broad-spectrum human diets that had a mix of marine and terrestrial resources
- 06/01/16--08:48: Endangered Kiwi Chick Hatches
Pollinators like butterflies, bees, beetles, flies, and moths help to pollinate almost 80 percent of the world’s flowering plants, one benefit of which is providing food for humans. Because their daily activities have such beneficial consequences for all life, it is important to make sure pollinators have places to rest, feed and reproduce.
James Gagliardi, lead horticulturist with Smithsonian Gardens at the Smithsonian’s National Museum of Natural History, says that the museum’s Butterfly Habitat Garden is setting the example by offering a balanced ecosystem for these pollinators right in the middle of Washington, D.C.
“Our garden offers butterflies a place to stop, pollinate, lay their eggs and get the rest they need,” Gagliardi says, pointing to the garden as a great example of how the Smithsonian is complying with the recent memorandum from President Obama asking federal buildings to make a concerted effort to be more pollinator friendly.
The Smithsonian has been making an effort to help pollinator populations for years, and continues to focus on helping educate the public about what they can do in their own backyard to attract and help pollinators.
“When people step into our garden they aren’t just getting to see the butterflies. We offer wonderful education panels so the average homeowner can produce the same pollinator-friendly spaces in their own yard,” Gagliardi says of the upgrades being made to the Butterfly Habitat Garden in anticipation of its upcoming name change to the Pollinator Garden. “The garden has always functioned as a pollinator garden. Now with the broad emphasis on supporting all pollinators we want our garden to reflect that commitment” Gagliardi says.
Gagliardi’s top three tips for creating a pollinator-friendly garden:
The Smithsonian’s National Museum of Natural History announced today that scientists with the museum’s Global Genome Initiative will attempt to capture the genomic diversity of half the world’s living plant genera in the next two years. To start, GGI scientists and field teams from the museum’s Department of Botany have begun sampling plants in the holdings of Smithsonian Gardens, the U.S. Botanic Garden and the U.S. Department of Agriculture’s U.S. National Arboretum.
Tissue samples from these collections will be preserved by freezing in liquid nitrogen and then stored indefinitely in the Smithsonian’s biorepository at its Museum Support Center in Suitland, Md. A pressed specimen of each plant will be housed in the U.S. National Herbarium at the National Museum of Natural History. Scientists worldwide will be able to access the samples through the Global Genome Biodiversity Network’s data portal.
“This pilot collaborative effort between the Smithsonian, U.S. National Arboretum and the U.S. Botanic Garden comes at an urgent time when the scientific community’s access to the world’s plant genomes—the blueprint of life—is limited due to biodiversity loss and lackluster genomic-research infrastructure,” says Jonathan Coddington, director of the National Museum of Natural History’s Global Genome Initiative. Scientists have estimated that the recent rate of species extinction is faster than at any other time in recorded history, perhaps 100 times faster than normal.
The gardens in Washington, D.C. contain plants from around the world, culled from desert climates to lush tropical rainforests. Young and aspiring scientists will assist the sampling project as part of GGI’s commitment to train the next generation of genomic scientists.
“Now more than ever, the Smithsonian is dedicated to increasing our knowledge about life on Earth through emerging genomic technologies and capabilities,” said John Kress, the Smithsonian’s interim Under Secretary for Science. “Partnering with botanical gardens around the world is an essential step in opening new doors to the hidden benefits that can emerge from the world’s plant genomes.”
To read a blog about this effort click here.
The post Smithsonian and Partners To Preserve Earth’s Genomic Plant Diversity appeared first on Smithsonian Insider.
Researchers have discovered a black hole that grew much more quickly than its host galaxy. The discovery calls into question previous assumptions on the development of galaxies.
The black hole was originally discovered using NASA’s Hubble Space Telescope, and was then detected in the Sloan Digital Sky Survey and by ESA’s XMM-Newton and NASA’s Chandra X-ray Observatory.
Benny Trakhtenbrot, from ETH Zurich’s Institute for Astronomy, and an international team of astrophysicists, performed a follow-up observation of this black hole using the 10 meter Keck telescope in Hawaii and were surprised by the results. The data, collected with a new instrument, revealed a giant black hole in an otherwise normal, distant galaxy, called CID-947. Because its light had to travel a very long distance, the scientists were observing it at a period when the universe was less than two billion years old, just 14 percent of its current age (almost 14 billion years have passed since the Big Bang).
An analysis of the data collected in Hawaii revealed that the black hole in CID-947, with nearly 7 billion solar masses, is among the most massive black holes discovered up to now. What surprised researchers in particular was not the black hole’s record mass, but rather the galaxy’s mass. The result was so surprising that two of the astronomers, including Hyewon Suh from the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, had to verify the galaxy mass independently. Both came to the same conclusion. The team reports its findings in the current issue of the scientific journal Science.
The distant young black hole observed by the team weighs about 10% of its host galaxy’s mass. In today’s local universe, black holes typically reach a mass of 0.2% to 0.5% of their host galaxy’s mass. That means this black hole grew much more efficiently than its galaxy – contradicting the models that predicted a hand-in-hand development. From the available Chandra data for this source, the researchers also concluded that the black hole had reached the end of its growth. However, other data suggests stars were still forming throughout the host galaxy. Contrary to previous assumptions, the energy and gas flow, propelled by the black hole, did not stop the creation of stars.
The galaxy could continue to grow in the future, but the relationship between the mass of the black hole and that of the stars would remain unusually large. The researchers believe that CID-947 could thus be a precursor of the most extreme, massive systems that we observe in today’s local universe, such as the galaxy NGC 1277 in the constellation of Perseus, some 220 million light years away from our Milky Way.
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the agency’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.
(Source: Chandra X-ray Center, Cambridge, Mass)
The Smithsonian is embarking on a multi-project partnership with Kickstarter, the funding platform for creative projects. The inaugural project will support conservation of Neil Armstrong’s Apollo 11 spacesuit at the National Air and Space Museum. The funds also will be used to digitize and exhibit the 46-year-old suit.
The campaign will start July 20, the anniversary of the first walk on the moon in 1969. Click HERE to learn more.
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Skygazers at northern latitudes are familiar with the W-shaped star pattern of Cassiopeia the Queen. This circumpolar constellation is visible year-round near the North Star. Tucked next to one leg of the W lies a modest 5th-magnitude star named HD 219134 that has been hiding a secret.
Astronomers have now teased out that secret: a planet in a 3-day orbit that transits, or crosses in front of its star. At a distance of just 21 light-years, it is by far the closest transiting planet to Earth, which makes it ideal for follow-up studies. Moreover, it is the nearest rocky planet confirmed outside our solar system. Its host star is visible to the unaided eye from dark skies, meaning anyone with a good star map can see this record-breaking system.
“Most of the known planets are hundreds of light-years away. This one is practically a next-door neighbor,” said astronomer Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics (CfA).
“Its proximity makes HD 219134 ideal for future studies. The James Webb Space Telescope and future large ground-based observatories are sure to point at it and examine it in detail,” said lead author Fatemeh (Ati) Motalebi of the Geneva Observatory.
The newfound world, designated HD 219134b, was discovered using the HARPS-North instrument on the 3.6-meter Telescopio Nazionale Galileo in the Canary Islands. The CfA is a major partner with the Geneva Observatory on the HARPS-North Collaboration, which includes several other European partners.
HARPS-North detects planets using the radial velocity method, which allows astronomers to measure a planet’s mass. HD 219134b weighs 4.5 times the mass of Earth, making it a super-Earth.
With such a close orbit, researchers realized that there was good possibility the planet would transit its star. In April of this year they targeted the system with NASA’s Spitzer Space Telescope. At the appropriate time, the star dimmed slightly as the planet crossed the star’s face. Measuring the depth of the transit gave the planet’s size, which is 1.6 times Earth. As a result, the team can calculate the planet’s density, which works out to about 6 g/cm3. This shows that HD 219134b is a rocky world.
But wait, there’s more! The team detected three additional planets in the system using radial velocity data. A planet weighing at least 2.7 times Earth orbits the star once every 6.8 days. A Neptune-like planet with 9 times the mass of Earth circles in a 47-day orbit. And much further out, a hefty fourth world 62 times Earth’s mass orbits at a distance of 2.1 astronomical units (200 million miles) with a “year” of 1,190 days. Any of these planets might also transit the star, so the team plans to search for additional transits in the months ahead.
HD 219134 is an orange Type K star somewhat cooler, smaller and less massive than our Sun. Its key measurements have been pinned down very precisely, which thus allows a more precise determination of the properties of its accompanying planets.
This discovery came from the HARPS-North Rocky Planet Search, a dedicated survey examining about 50 nearby stars for signs of small planets. The team targeted nearby stars because those stars are brighter, which makes follow-up studies easier. In particular, additional observations might allow the detection and analysis of planetary atmospheres.
HD 219134 was one of the closest stars in the sample, so it was particularly lucky to find that it hosts a transiting planet. This system now holds the record for the nearest transiting exoplanet. As such, it likely will be a favorite for researchers for years to come.
The paper describing this research has been accepted for publication in the journal Astronomy & Astrophysics.
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The National Air and Space Museum is asking Star Trek fans to search their memory banks for firsthand, pre-1976 images or film of the original studio model of the USS Enterprise. Conservators are working to restore the ship to its appearance from August 1967, and they will use the primary-source photos as reference materials for the project. Hailing frequencies are open to the public at StarshipEnterprise@si.edu.
Sept. 8 marks the 49th anniversary of the original Star Trektelevision series. The 11-foot-long studio model used in all 79 episodes is currently in the Emil Buehler Conservation Laboratory at the Steven F. Udvar-Hazy Center in Chantilly, Va. It will go on display in the museum’s Boeing Milestones of Flight Hall in 2016. The public can watch for updates on the museum’s social channels and join in the conversation by using #MilestonesofFlight.
The Enterprise model has undergone eight major modifications since it was built in 1964, both during and after production of the series. The current restoration will restore the ship to its August 1967 appearance, during and after the production of the episode “The Trouble with Tribbles,” which is the last time the Enterprise was altered throughout the original Star Trek.
Fans’ first contact was in April 1972, when the model appeared at Golden West College in Huntington Beach, Calif., during Space Week, a 10-day gathering of space-related activities attended by more than 50,000 people. In 1974 and ’75 the ship was displayed in the Smithsonian’s Arts & Industries Building in Washington, D.C., while the National Air and Space Museum’s new home on Independence Avenue was under construction.
Firsthand, original images or film of the ship under construction, during filming or on public display at any time before 1976 are particularly useful. Screen captures from the television series, or existing images and clips available online, are not needed. To find out more about submitting material, the public can contact StarshipEnterprise@si.edu.
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Scientists at the Smithsonian Tropical Research Institute (STRI) in Panama compared the diets of two caterpillar species, expecting the one that exclusively consumed plants containing toxic chemicals would more easily incorporate toxins into its body than the one with a broad diet. They found the opposite. The new finding, published in the Journal of Chemical Ecology, flies in the face of a long-held theory that specialist insects are better adapted to use toxic plant chemicals than non-specialists.
The discovery opens new avenues for understanding plant-insect coevolution—an ongoing arms race of plants producing new defense chemicals and insects finding ways around them. Toxic plant chemicals also have potential medical applications against microbes or cancer cells.
The tropical plant Vismia baccifera protects itself by producing a number of repellent chemicals, including three compounds that are toxic to living cells. Few plant-eating insects can stomach such a cocktail, but for those that can, the advantages are clear—less competition for a meal, and a chemical toolkit they can use in their own defense.
Skipper butterfly, Pyrrhopyge thericles, caterpillars only eat plants in the genus Vismia. The caterpillars of a large moth,Periphoba arcaei, have a much broader diet, including Vismiaplants and many others. Brightly colored caterpillars, one with flamboyant stripes, and the other blue-green with bristles, teach predators to associate their striking looks with toxicity—a defensive warning system known as aposematism.
“Brightly colored plant-eating insects help us to identify plants containing compounds active against important human diseases,” said Todd Capson, a former associate scientist at STRI, who oversaw visiting researcher Ciara Raudsepp-Hearne, the lead author of the new study. The work documents the first known occurrence of Vismia chemicals in butterflies and moths.
The researchers analyzed several life stages of the two caterpillar species for the presence and concentration of plant toxins called vismiones. While two vismione compounds are found at a ratio of 1:6 in the plants, in the specialist butterfly caterpillars the compounds were barely detectable, and at roughly equal ratios. Meanwhile, the generalist moth caterpillars contained significant quantities of the rarer of the two compounds, suggesting that they were able to actively store this plant chemical in their own bodies. Both caterpillars’ fecal matter revealed a 1:2 ratio of the plant compounds, indicating that their bodies might uptake compounds selectively or convert molecules of one type over the other.
“We know very little about just how each plant-eating insect handles these chemicals—how they store them or eliminate them,” said STRI staff scientist and study coauthor Annette Aiello. Some insects might isolate the compounds so they do not cause them harm, while others might convert the molecules into forms that are harder for scientists to detect. Insects that process harmful toxins without damaging their own cells have a survival advantage. For a generalist species, said Aiello, “the ability to sequester toxic compounds might be an early evolutionary breakthrough,” the first step along the pathway to becoming a toxic plant specialist.
Previous work suggests that the presence of plant-eating insects sporting bright warning colors may signal plants containing potentially useful chemicals. And while specialist insects share an obvious history with their host plants, the new study suggests that generalist insects also may play an important role in the chemical arms race that drives plant-insect coevolution. “The study of insects with generalist diets can sometimes yield results that are just as rewarding as the study of specialists,” Capson said.
This study was conducted through STRI and McGill University’s collaborative Neotropical Environment Option program. The work was supported in part by Panama’s International Cooperative Biodiversity Groups program. The authors’ present affiliations include STRI, McGill, the Centro de Investigaciones Farmacognósticas de la Flora Panameña, University of the Western Cape and the National Bureau of Science, Technology and Innovation of Panama.
Although useful to Tarzan, vines endanger tropical forests’ capacity to store carbon. In a major experimental study in Panama, Smithsonian researchers showed that woody vines, or lianas, slow tropical forest tree growth and may even cause premature tree death. Lianas reduced aboveground carbon uptake by more than three-quarters, threatening the forests’ ability to buffer climate change.
Tropical forests account for a third of the total carbon fixed by photosynthesis. Lianas’ increasing abundance may be driven by changing climate, increased disturbance or by more severe seasonal drought. By reducing the ability of tropical forests to accumulate and store carbon released through burning fossil fuels, lianas could cause a positive feedback loop, accelerating climate change.
“This study has far-reaching ramifications,” said co-author Stefan Schnitzer, a biology professor at Marquette University and a long-term research associate at the Smithsonian Tropical Research Institute. “Lianas contribute only a small fraction of the biomass in tropical forests, but their effects on trees dramatically alter how carbon is accumulated and stored.”
Proceedings of the National Academy of Sciences published the article co-authored by Geertje van der Heijden, a postdoctoral fellow at STRI and in Schnitzer’s lab, and Jennifer Powers, a professor at the University of Minnesota.
Lianas are characteristic of lowland tropical forests, often making up more than 25 percent of species and woody stems. Because they depend on trees for support as they climb into sunlit treetops, they can invest a greater percentage of their own biomass in leaves.
Previous research by Schnitzer and colleagues showed that lianas can have significant negative effects on forest biomass growth and accumulation. These studies, however, focused primarily on tree growth, were restricted to forest gaps or were only observational. In this experimental study in Panama’s Barro Colorado Nature Monument, all lianas were cut in eight experimental plots in a 60-year-old secondary forest, but were left intact in eight others. For the next three years, researchers monitored the growth in diameter of trees and lianas in the plot, and collected and weighed dead leaves and other debris falling from the forest canopy.
By the third year, lianas reduced net biomass accumulation by 76 percent per year in plots where they were present compared to where they had been removed. This decrease was due both to lower tree growth and to an increase in tree mortality where lianas were present. The proportion of biomass in leaves versus wood differed as well: forest canopy productivity–mostly leaves–decreased by 14 percent in liana-free plots, while the productivity of woody stems rose by almost 65 percent. Lianas not only lowered biomass accumulation, but also shifted it from wood, which stores carbon for a long time, to leaves, which rot quickly and release carbon back to the atmosphere.
These results have dramatic implications for the capacity of tropical forests to serve as a sink for carbon in the future. Simulating the change of biomass stocks over the next 50 years in forests with lianas and without them, the authors found lianas could reduce long-term storage of carbon by 35 percent. Even greater reductions could take place if liana-tree competition intensifies due to the spread of lianas, or causes an increase in the fast-growing tree species with low wood density.
While lianas clearly reduce the capacity for tropical forests to store carbon, Schnitzer emphasizes that lianas are an important and valuable component of tropical forests: “In terms of carbon, lianas may be detrimental; however, lianas provide a wide range of resources for wildlife, such as fruits, seeds and fresh leaves, and by connecting trees together lianas provide aerial pathways that are used by the vast majority of arboreal animals to move through the forest.”
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Smithsonian Secretary David J. Skorton will accept a Nano Bible from Peretz Lavie, president of the Technion-Israel Institute of Technology, at the Smithsonian’s National Museum of American History on Oct. 30. The Nano Bible will be part of the Smithsonian Libraries collection, housed in the Dibner Library of the History of Science and Technology at the National Museum of American History.
The Nano Bible was produced by researchers at the Russell Berrie Nanotechnology Institute at the Technion-Israel Institute of Technology in Haifa, Israel. Engraved on a gold-plated silicon chip the size of a sugar grain, the bible’s text consists of more than 1.2 million letters carved with a focused beam of gallium ions. The text engraved on the chip must be magnified 10,000 times to be readable.
“We are excited to enrich the Libraries’ collections with this marvelous gift, which marries one of the world’s oldest and most significant texts with one of the newest technologies of the 21st century,” said Nancy E. Gwinn, director of Smithsonian Libraries. “As one of our principal values is to share our collections with the public, it is appropriate that the only copy in the United States be located here, as part of the national collections.”
At less than 100 atoms thick, the Nano Bible demonstrates how people can process, store and share data through tiny dimensions using nanotechnology. The Smithsonian’s Nano Bible will be the first one received in the United States.
Throughout 2015 the Smithsonian Environmental Research Center (SERC) in Edgewater, Md., has marked its 50th year of operation. Now there’s another reason for SERC to celebrate: One year after opening its Leadership in Energy & Environmental Design (LEED)-certified Mathias Laboratory, SERC has received a prestigious GreenGov Presidential Award for the building’s green design and sustainable operation.
The White House announced eight awards in seven different categories on Nov. 23. The recipients were people and projects that have made extraordinary achievements in the pursuit of President Obama’s Federal Sustainability goals.
As one of the most energy-efficient laboratories in the country, the Mathias Lab received the GreenGov Building the Future Award. The lab, which is LEED-certified “Platinum,” is the Smithsonian’s greenest building and emits 37 percent less carbon dioxide than a comparable laboratory that does not meet LEED standards.
“This award recognizes SERC’s commitment to lead a sustainable future and help reverse climate change; and it provides a wonderful facility for our innovative research on the most pressing environmental problems of the next 50 years,” says Anson Hines, SERC director.
The new laboratory’s specially designed features include:
• Roof-mounted panels that provide sun-heated hot water to an innovative interconnected system that recycles 100 percent of its water
• An HVAC system supplied by a large geothermal well field (250 wells 430 feet deep)
• Low-flow fume hoods for chemistry experiments
• Space for nearly 650 solar panels that provide almost 16 percent of the building’s electricity
With its completion, LEED certification and now the honor of a GreenGov Presidential Award, SERC’s Mathias Lab has set the bar high for the Smithsonian.
“Our current goal for all Smithsonian new construction and renovation is LEED Gold, but the Mathias Laboratory exceeded our policy by achieving LEED Platinum certification,” says Nancy Bechtol, director of Smithsonian’s Office of Facilities Engineering and Operations. “Our next objective is to build a Net Zero facility at SERC, and we are up for the challenge!”
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Prehistoric human populations of hunter-gatherers in a region of North America grew at the same rate as farming societies in Europe, according to a new radiocarbon analysis involving researchers from the University of Wyoming and the Harvard-Smithsonian Center for Astrophysics.
The findings challenge the commonly held view that the advent of agriculture 10,000-12,000 years ago accelerated human population growth. The research is reported this week in the Proceedings of the National Academy of Sciences, a major scientific journal.
“Our analysis shows that transitioning farming societies experienced the same rate of growth as contemporaneous foraging societies,” says Robert Kelly, University of Wyoming professor of anthropology and co-author of the PNAS paper. “The same rate of growth measured for populations dwelling in a range of environments, and practicing a variety of subsistence strategies, suggests that the global climate and/or other biological factors — not adaptability to local environment or subsistence practices — regulated long-term growth of the human population for most of the past 12,000 years.”
The lead author of the paper is Jabran Zahid of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Erick Robinson, post-doctoral researcher in the University of Wyoming’s Department of Anthropology, also participated in the research.
While the world’s human population currently grows at an average rate of 1 percent per year, earlier research has shown that long-term growth of the prehistoric human population beginning at the end of the Ice Age was just 0.04 percent annually. That held true until about 200 years ago, when a number of factors led to higher growth rates.
For their research, the UW and Harvard-Smithsonian scientists analyzed radiocarbon dates from Wyoming and Colorado that were recovered predominantly from charcoal hearths, which provide a direct record of prehistoric human activity.
For humans in the region that is now Wyoming and Colorado between 6,000 and 13,000 years ago — people who foraged on animals and plants to survive — the analysis showed a long-term annual growth rate of 0.041 percent, consistent with growth that took place throughout North America. During that same period, European societies were farming or transitioning to agriculture, yet the growth rate there was essentially the same.
“The introduction of agriculture cannot be directly linked to an increase in the long-term annual rate of population growth,” the researchers wrote.
In general, similar rates of growth — around 0.04 percent — were measured for prehistoric human populations across a broad range of geographies and climates, the scientists say. “This similarity in growth rates suggests that prehistoric humans effectively adapted to their surroundings such that region-specific environmental pressure was not the primary mechanism regulating long-term population growth.”
Instead, the factors that controlled long-term population growth during that period likely were global in nature, such as climate change or biological factors affecting all humans, such as disease.
While concluding that population growth held steady overall at about 0.04 percent annually for thousands of years, the paper acknowledges that there were short-term fluctuations in human growth rates in certain regions lasting from a few hundred to 1,000 years. The authors suggest further statistical analysis of radiocarbon dates of human remains to study the mechanisms regulating population growth.
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Many animals change sex at some point in their lives, often after reaching a certain size. Snails called slipper limpets begin life as males, and become female as they grow. A new Smithsonian study shows that when two males are kept together and can touch one another, the larger one changes to female sooner, and the smaller one later. Contact, rather than chemicals released into the water, is necessary for the effect.
“I was blown away by this result,” said Rachel Collin, staff scientist at the Smithsonian Tropical Research Institute (STRI). “I fully expected that the snails would use waterborne cues to see their world.”
The article, co-authored by Collin and former STRI intern Allan Carrillo-Baltodano, now a pre-doctoral student at Clark University, was published in The Biological Bulletin.
Tropical slipper limpets, Crepidula cf. marginalis, live under rocks in intertidal areas along the shore, obtaining food by filtering plankton and other particles from the water. Their thin, flattened shells have a built-in shelf. When flipped over, they resemble men’s house slippers. Often found in clusters, they occur alone or as pairs or trios consisting of a large female with one or two smaller males riding piggyback on her shell.
A male limpet has a comparatively enormous penis–sometimes as long as his entire body–which rather incongruously emerges from the right side of his head. This elongated apparatus is necessary to extend around and under the female’s shell in order to reach her genital opening. When a snail changes sex, the penis gradually shrinks and then disappears at the same time that female organs develop. It is thought that this kind of sex change is advantageous because large animals are able to produce larger numbers of eggs as females, while small males can still produce plenty of sperm (which require much less energy to make than eggs).
In experiments, two males differing slightly in size were kept in small cups containing seawater. In some cups they were allowed to be in contact with one another, while in others a mesh barrier kept them apart while allowing water to pass through. The larger snails in the pairs in direct contact with their partners grew more quickly and changed into females sooner than those kept apart. Conversely, the smaller member of a pair that was in contact delayed sex change compared to ones separated by mesh.
In sex-changing coral-reef fishes, visual, behavioral and chemical cues may all influence switching by individuals that associate with each other. Slipper limpets, which are sedentary and have poor vision, were initially expected to depend more on waterborne chemical cues, already known to affect other aspects of their behavior. Surprisingly, slipper limpets turned out to be like fishes in showing a greater response to behavioral interactions or perhaps contact-based chemical cues, than waterborne signals.
“Slipper snails don’t move around much, so you don’t really think of them having complex reactions to each other,” Collin said. “But this study shows that there is more going on there than we thought.”
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How more than 1,000 tree species may occur in a small area of forest in Amazonia or Borneo is an unsolved mystery. Their ability to co-exist may depend on how trees get along with their neighbors. A new study based, in part, on data from the Smithsonian’s Forest Global Earth Observatory (ForestGEO) network shows that trees worldwide compete in some of the same ways, making simpler models of forest response to climate change possible.
Published in Nature, the study demonstrated how ‘personal’ traits such as wood density and leaf morphology influence a tree species’ ability to compete. There are trade-offs. Species with lighter wood usually grow more quickly than species with denser wood. But species with lighter wood also tend to die sooner and be poor competitors. Trees with dense tissues have more impact on their neighbors.
“We uncovered straightforward relationships between tree shape, growth rates and competitive abilities that organize tree communities around the world,” said S. Joseph Wright, co-author and staff scientist at the Smithsonian Tropical Research Institute in Panama.
Tree-to-tree interactions are difficult to study because trees grow slowly and are long-lived. Lead author Georges Kunstler of the Institut National de Recherche en Sciences et Technologies pour l’Environnement et l’Agriculture in France and colleagues used data from 3 million trees of 2,500 species growing at 140,000 sites from all forested biomes, to determine how traits influence tree competition. The study incorporated data from ForestGEO plots, coordinated by the Center for Tropical Forest Science at the Smithsonian Tropical Research Institute, including forest data from Barro Colorado Island, Panama; Luquillo, Puerto Rico; and Fushan, Taiwan.
Their findings strongly support a long-standing ecological idea about how forest succession influences tree diversity. In young forests, trees are more spread out, giving fast-growing species an advantage when there is little competition from surrounding trees. But as a forest matures and neighbors become more abundant, slower-growing trees win out because they are better competitors for resources like minerals, water and light. One of the most prominent ideas about how forest diversity is maintained is that trees can avoid competition by being different from their neighbors in the way they use resources and their life-history strategy. If this were the case, any trait could be advantageous as long as it was different from those of neighboring trees. Instead, this study shows that certain traits are more advantageous at different stages of forest succession whether or not they differ from those of neighbors.
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The bush dog is one of the most enigmatic of the world’s canid species, seldom seen throughout its range in Central and South America. New data from photos taken by automated camera traps in remote areas in Panama, along with other sightings, show the species to be widespread in the country. The new study, co-authored by Smithsonian Research Associate Ricardo Moreno, will assist conservation planning for this near-threatened species.
“Our group of biologists from Yaguará Panama and collaborators are working on an article about big mammals using camera trapping data that spans Panama from the Costa Rican border to the Colombian border,” Moreno said. “The bush dog is one of the rarest species that we photograph.”
Bush dogs, Speothos venaticus, are short-legged and stubby, standing only about a foot tall at the shoulder. They live mainly in tropical forests but have also been recorded in fragmented and altered habitats. Hunting in packs of up to 10 animals, bush dogs give high-pitched whines to maintain contact and yap like puppies when they chase their prey. They feed mostly on large forest rodents like agoutis and pacas, but at one site in Brazil, they mainly ate armadillos. Fierce for their size, a pack of six once was seen chasing a tapir, an animal almost 20 times a bush dog’s weight. Although active by day, bush dogs are remarkably hard to see and are very rarely reported even where they are known to occur.
Digital camera traps, which take pictures automatically when their infrared sensors detect an animal’s body heat, are used in many wildlife studies. Camera traps were set out as part of surveys for other mammals, including jaguars. The cameras fortuitously snapped photos of bush dogs at four sites ranging from Cerro Pirre near the Colombian border in eastern Panama, to Santa Fe National Park in the western part of the country. To give some idea of the difficulty of studying the species, photos were obtained on only 11 occasions out of more than almost 32,000 camera-days (the number of cameras multiplied by the number of days they were in operation).
The article reports bush dog sightings from five additional sites, including Fortuna west of Santa Fe, showing the species is found in suitable habitat nearly throughout Panama. Panama is the only country in Central America where the species is known to occur, aside from a few unconfirmed sightings in easternmost Costa Rica near the Panamanian border. “We think that it will soon cross the border into Costa Rica,” Moreno said.
The International Union for Conservation of Nature has estimated that bush dog populations have declined by up to 25 percent in the past 12 years, and has classified it as “near-threatened” globally. Unlike other some other carnivores in Panama, such as jaguar, puma and coyote, bush dogs do not appear to be directly persecuted by humans. The main threats are habitat loss and encroachment–15 percent of Panama’s forests were lost between 1990 and 2010. Bush dogs have very large home ranges for animals of their size, as much as 270 square miles, and they may require large tracts of forest to survive. Other threats include reduction of the abundance of their prey from hunting by humans and exposure to diseases carried by dogs used by hunters.
Cobia, a promising fish for aquaculture, lives throughout the world’s oceans except in the Central and Eastern Pacific. In August 2015, a large number of young fish escaped from offshore cages in Ecuador. Cobia have recently been reported from the Colombian and Panamanian Pacific coast, indicating their rapid spread from the release site. Voracious carnivores, cobia could have far-reaching impacts on fisheries and marine ecology in the Eastern Pacific, Smithsonian scientists warn.
“The havoc caused by invasive Indo-Pacific lionfish throughout the Caribbean provides a compelling lesson about the strong adverse effects that alien marine fish can have on naïve ecosystems,” said D. Ross Robertson, staff scientist at the Smithsonian Tropical Research Institute.
“The extraordinary success of the lionfish in the Caribbean is due in large part to its being a type of predator with no near relatives or ecological analogs among the Caribbean fish fauna,” Robertson said. “As cobia is the only species in its family, which is most closely related to remoras or shark-suckers, it too represents an unusual type of predator for the tropical East Pacific, which only increases both the degree of uncertainty about its effects and the potential for major disruption of the area’s ecosystems.”
Cobia (Rachycentron canadum) are streamlined in shape with nearly smooth skin, brown above and white below, with a darker brown stripe on the side. Young fish have strong horizontal dark brown and white stripes. They attain a maximum length of two meters (78 inches) and maximum weight of 78 kilograms (172 pounds). They eat crustaceans (especially crabs), squid and fish. Cobia are also known as black kingfish, black salmon (although they are not related), ling, crabeater and several other names.
The species is found in warmer waters on both sides of the Atlantic, and throughout the Indian and Western Pacific Oceans. Cobia occur both offshore and in coastal waters and estuaries and are highly migratory. Eggs and larvae float among plankton, making them capable of spreading widely.
Cobia are considered to be an excellent food fish, with firm texture and good flavor. Although the species is relatively uncommon in most of its natural range, it has high potential for aquaculture due to its hardiness and exceptionally fast growth. Cobia are now being cultivated in Taiwan, Vietnam, China, the Philippines, Indonesia, Belize, Brazil and on Panama’s Caribbean Coast.
Many introduced or non-native species have little or no adverse effect on local ecosystems. However, some become invasive and harm native species via predation, competition or other negative effects. Although examples of invasive species are common in land and freshwater habitats, until recently there were no documented cases in marine environments. In the early 1990s, Indo-Pacific lionfish (Pterois sp.) were introduced to the Florida/Bahamas area, and have since spread throughout much of the Western Atlantic and Caribbean. Rapacious predators on shrimp and fishes and protected from being eaten by venomous spines, lionfish have produced dramatic changes in coral reef communities in their new range.
Fishermen, marine resources agencies and marine ecologists should be aware that cobia are now present in the Eastern Pacific and the potential deleterious effects they may have. While it is not yet certain that they will become established, their broad environmental tolerance and rapid growth make this a distinct possibility. Catches or sightings (verified with photographs) of cobia in Pacific waters should be noted and reported to D. Ross Robertson firstname.lastname@example.org.
In the first volume of the Secret Smithsonian Adventures graphic-novel series from Smithsonian Books, The Wrong Wrights, four middle-school kids visit the Smithsonian’s National Air and Space Museum to find a completely different museum than the one they expected.
On a field trip to the museum, Dominique, Eric, Josephine and Ajay discover that all the airplanes and space ships are gone—in their place are balloons, blimps and dirigibles. Using their knowledge of science and history, the friends set out to solve the mystery of what is going on and who is at the bottom of it.
Al, a museum “fabrications specialist” at the museum leads them back in time to Manhattan’s Battery Park 1909 where early aviators are preparing to demonstrate their flying machines. A computer named “Smitty” (Smithsonian Archive Interface Facilitator) guides the group, and they meet-up with aviation pioneers Orville and Wilbur Wright, Glenn Curtiss and Thomas Scott Baldwin. They also meet Katharine Wright, Orville and Wilbur’s sister, who assisted her brothers with their experiments.
As the kids foil those who are trying to alter aviation history, they learn about aerodynamics and other aviation principles. Their work returns the Air and Space Museum to normal with its display of airplanes and space ships, and the Wright brothers’ place in history is restored.
This colorful book is written by Steve Hockensmith and Chris Kientz and illustrated by Lee Nielsen. Geared to 9-to-12-year-old readers and their parents, grandparents, teachers and librarians, The Wrong Wrights is the first graphic novel in a Smithsonian Book’s series that will include adventures set in the Smithsonian’s National Museum of Natural History (Claws and Effect) and the National Museum of American History.
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Nearly four billion years ago, life arose on Earth. Life appeared because our planet had a rocky surface, liquid water, and a blanketing atmosphere. But life thrived thanks to another necessary ingredient: the presence of a protective magnetic field. A new study of the young, Sun-like star Kappa Ceti shows that a magnetic field plays a key role in making a planet conducive to life.
“To be habitable, a planet needs warmth, water, and it needs to be sheltered from a young, violent Sun,” says lead author Jose-Dias Do Nascimento of the Harvard-Smithsonian Center for Astrophysics (CfA) and University of Rio G. do Norte (UFRN), Brazil.
Kappa Ceti, located 30 light-years away in the constellation Cetus, the Whale, is remarkably similar to our Sun but younger. The team calculates an age of only 400-600 million years old, which agrees with the age estimated from its rotation period (a technique pioneered by CfA astronomer Soren Meibom). This age roughly corresponds to the time when life first appeared on Earth. As a result, studying Kappa Ceti can give us insights into the early history of our solar system.
Like other stars its age, Kappa Ceti is very magnetically active. Its surface is blotched with many giant starspots, like sunspots but larger and more numerous. It also propels a steady stream of plasma, or ionized gases, out into space. The research team found that this stellar wind is 50 times stronger than our Sun’s solar wind.
Such a fierce stellar wind would batter the atmosphere of any planet in the habitable zone, unless that planet was shielded by a magnetic field. At the extreme, a planet without a magnetic field could lose most of its atmosphere. In our solar system, the planet Mars suffered this fate and turned from a world warm enough for briny oceans to a cold, dry desert.
The team modeled the strong stellar wind of Kappa Ceti and its effect on a young Earth. The early Earth’s magnetic field is expected to have been about as strong as it is today, or slightly weaker. Depending on the assumed strength, the researchers found that the resulting protected region, or magnetosphere, of Earth would be about one-third to one-half as large as it is today.
“The early Earth didn’t have as much protection as it does now, but it had enough,” says Do Nascimento.
Kappa Ceti also shows evidence of “superflares” — enormous eruptions that release 10 to 100 million times more energy than the largest flares ever observed on our Sun. Flares that energetic can strip a planet’s atmosphere. By studying Kappa Ceti, researchers hope to learn how frequently it produces superflares, and therefore how often our Sun might have erupted in its youth.
This research has been accepted for publication in The Astrophysical Journal Letters and is available online. This set of Kappa Ceti observations were part of the Bernard Lyot Telescope’s Bcool Large Program.
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New high-speed videos of 14 species of tiny Mecysmaucheniid “trap-jaw” spiders have revealed that some species can snap their mouth parts shut at incredibly fast speeds and with super-spidey power.
Hannah Wood, curator of spiders at the Smithsonian’s National Museum of Natural History, used a high-speed camera to record the spiders—some at 40,000 frames a second. Her videos showed that when target prey came close enough, the spiders snapped their jaws (chelicerae) shut with incredible power and speed. This type of predatory behavior had been observed before in ants, but not in arachnids.
Aside from sheer speed, the power output from four of the spider species exceeded the known power output of their muscles, Wood and colleagues discovered. This finding implies that the spiders’ movements are not directly powered by the tiny muscles of their jaws.
In this video a trap-jaw spider snaps its jaws with lightning speed.
Instead, other structural mechanisms must be involved that allow trap-jaw spiders to store energy required to produce their high-powered, lightning-quick movements. The biological ability of these spiders’ to release stored energy almost instantaneously results in the power being amplified. Mecysmaucheniid spiders live exclusively in New Zealand and southern regions of South America
Wood and coauthors describe the anatomical differences between trap-jaw spiders and their close relatives in a paper in the scholarly journal Current Biology. The research team is conducting additional investigations to better understand the underlying mechanism for storing energy for trap-jaw spiders’ power-amplified behavior.
Using DNA analysis, Wood and team also found that the high-speed, power-amplified strikes have independently evolved at least four different times—a phenomena known as convergent evolution—within the Mecysmaucheniid family. The findings also contribute to Wood’s broader investigation into the evolution of the spider tree of life, shedding new light on how the bizarre “head” anatomy of trap-jaw spiders and their relatives may have allowed them to evolve unique survival abilities like power-amplified strikes.
“This research shows how little we know about spiders and how much there is still to discover,” Wood says. “The high-speed predatory attacks of these spiders were previously unknown. Many of the species I have been working with are also unknown to the scientific community.”
“Many of our greatest innovations take their inspiration from nature,” Wood adds. “Studying these spiders may give us clues that allow us to design tools or robots that move in novel ways.”
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For the first time, scimitar-horned oryx are going to be reintroduced to the wild in Chad. Extinct in the wild since the mid-1980s, the species’ return is the result of the Environment Agency—Abu Dhabi (EAD) and the government of Chad’s Scimitar-horned Oryx Reintroduction Program. Researchers from the Smithsonian Conservation Biology Institute (SCBI) will be working as part of the program to monitor the herd remotely after the reintroduction. A team of rangers trained by EAD and the Sahara Conservation Fund (SCF) will monitor the herd on the ground in Chad.
“This ambitious and historic recovery effort was made possible by the establishment of a ‘world herd’ of scimitar-horned oryx in Abu Dhabi, and a decades-long history of excellence in the care and management of this species in human care around the world,” said Steve Monfort, the John & Adrienne Mars director of SCBI, who was in Chad when the oryx arrived. “Restoring oryx to the wild will have a huge and positive impact on the conservation and management of the entire Sahelian grasslands ecosystem. We are thrilled to play a role in this incredible partnership designed to restore the species to its rightful place in the wild.”
Twenty-five scimitar-horned oryx arrived in Chad by airplane from Abu Dhabi March 16 and were taken to the Ouadi Rimé-Ouadi Achim Game Reserve. It was the first time in 30 years any oryx had been in the country. The oryx will initially be held in a large fenced area to acclimate them to their new home at the Reserve. They will be fully released this summer, when the rainy season makes conditions in their native desert habitat more favorable.
Before the full release of the herd, each oryx will be fitted with a GPS-satellite collar and monitored by scientists at SCBI and the Zoological Society of London. The data they collect will be used to track and help protect the animals, gather behavioral data on the species and study their ecology. The data will help future reintroduction efforts.
The collars were tested on scimitar-horned oryx herds living at SCBI in Front Royal, Va., and at Fossil Rim Wildlife Center in Texas in separate one-month trials. The trials demonstrated that the oryx were not negatively affected by wearing the collars. Before the full release this summer, SCBI scientists will travel to Chad to fit the oryx with collars and conduct final tests of the satellite data transmission and analysis protocols before the animals are released.
SCF and EAD have also trained a team of local wildlife experts and rangers to monitor the oryx after they are reintroduced. To help with their continued protection, the team will organize community outreach programs about the oryx. The reintroduction program is working to build a self-sustaining population of 500 wild oryx over the next five years. EAD is developing a genetically diverse “world herd” of oryx, including animals originally from the United States, Europe and United Arab Emirates. Those animals will be part of future reintroductions.
The scimitar-horned oryx, a desert antelope, was declared extinct in the wild by the International Union for Conservation of Nature in 2000. Unregulated hunting was the primary cause of the scimitar-horned oryx’s extinction in the wild. Today, however, the threat from largely unregulated pastoral development and habitat loss are major concerns. The world’s largest single population of scimitar-horned oryx living in human care—numbering approximately 3,000 individuals—is in the United Arab Emirates.
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Seven fossil teeth exposed by the Panama Canal expansion project are the first evidence of a monkey on the North American continent before the Isthmus of Panama connected it to South America 3.5 million years ago. A team including Carlos Jaramillo, staff scientist at the Smithsonian Tropical Research Institute (STRI), published this discovery online in the journal Nature. They named the new monkey species Panamacebus transitus in honor of Panama and the monkey’s movement across the ancient seaway that divided North and South America.
The 21 million-year-old teeth were found in the Las Cascadas Formation during a five-year intensive fossil salvage project by field crews from STRI, the University of Florida and the New Mexico Museum of Natural History and Science. Most of the mammal groups represented in the Las Cascadas formation have North American origins, despite the fact that South America is much closer, supporting the idea that Central America and western Panama represented a long peninsula extending south from North America.
During the salvage project, researchers rushed in behind engineers as they dynamited the steep canal banks. The researchers collected exposed fossils and described each location before heavy rains and fast-growing vegetation obscured evidence of the dramatic tectonic events that lifted the land bridge out of the sea to connect North and South America.
“I asked my boss for a million dollars to dig a hole in the ground,” Jaramillo said. “Then the Panamanian people voted for the Panama Canal Authority to spend $5.6 billion dollars to expand the Canal and unlocked a treasure trove for us, containing this new monkey species and many other fossils.”
“We suggest that Panamacebus was related to the capuchin (also known as “organ-grinder” monkeys) and squirrel monkeys that are found in Central and South America today,” said Jonathan Bloch, curator of vertebrate paleontology at the Florida Museum of Natural History on the University of Florida campus and lead author on the study. “Prior to this discovery, New World monkeys were thought to have evolved in isolation on South America, cut off from North America by a wide seaway.”
Before the monkey teeth were discovered, the oldest evidence of movement of a mammal from South to North America are 8.5–9 million-year-old fossil remains of giant sloths. The authors of this report suggest two explanations: 1) that mammals from South America were more adapted to life in the South American-derived forests still found in Panama and Costa Rica than to other forest types characteristic of Northern Central America or 2) that the lack of exposed fossil deposits throughout Central America means that evidence of these dispersals has yet to be revealed.
The U.S. National Science Foundation contributed $3.8 million as part of the Panama Partnership for International Research and Education led by researchers from the Florida Museum of Natural History. As the expansion nears its completion, the tally of fossils identified so far includes bats, horses, squirrels, small camelids, crocodiles, turtles and ferocious bear dogs. The new, wider third lane of the Panama Canal will open for business June 26.
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When is a blue bird not blue? The answer to this question is always. There actually is no such thing as a blue bird. To find out why, Smithsonian Insider asked Scott Sillett, a wildlife biologist at the Smithsonian Migratory Bird Center.
“Red and yellow feathers get their color from actual pigments, called carotenoids, that are in the foods birds eat,” Sillett explains. “Blue is different―no bird species can make blue from pigments. The color blue that we see on a bird is created by the way light waves interact with the feathers and their arrangement of protein molecules, called keratin. In other words, blue is a structural color. Different keratin structures reflect light in subtly different ways to produce different shades of what our eyes perceive as the color blue. A blue feather under ultraviolet light might look uniformly gray to human eyes.”
The National Zoo’s red panda habitat on Asia Trail reopened to the public Tuesday, May 10. Tusa and Asa explored their new home which has a brand new “retreat.” The retreat includes four indoor enclosures complete with air-conditioning and heating. The retreat has a viewing window, allowing visitors to see the red pandas when they choose to spend time inside. Three of the indoor enclosures reach 11 feet high and one reaches 9 feet. There are ample structures inside for the arboreal animals to climb as well.
Native to China, Nepal, India, and Bhutan red pandas are listed as endangered by the International Union for Conservation of Nature. Conservationists estimate that fewer than 10,000 red pandas remain in the wild. In the past 18 years, populations have declined by 50 percent due to human expansion, habitat fragmentation and wildlife trafficking for traditional medicine and the pet trade.
Earlier this year scientists presented evidence for Planet Nine, a Neptune-mass planet in an elliptical orbit 10 times farther from our Sun than Pluto. Since then theorists have puzzled over how this planet could end up in such a distant orbit.
New research by astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) examines a number of scenarios and finds that most of them have low probabilities. Therefore, the presence of Planet Nine remains a bit of a mystery.
“The evidence points to Planet Nine existing, but we can’t explain for certain how it was produced,” says CfA astronomer Gongjie Li, lead author on a paper accepted for publication in the Astrophysical Journal Letters.
Planet Nine circles our Sun at a distance of about 40 billion to 140 billion miles, or 400 – 1500 astronomical units. (An astronomical unit or A.U. is the average distance of the Earth from the Sun, or 93 million miles.) This places it far beyond all the other planets in our solar system. The question becomes: did it form there, or did it form elsewhere and land in its unusual orbit later?
Li and her co-author Fred Adams (University of Michigan) conducted millions of computer simulations in order to consider three possibilities. The first and most likely involves a passing star that tugs Planet Nine outward. Such an interaction would not only nudge the planet into a wider orbit but also make that orbit more elliptical. And since the Sun formed in a star cluster with several thousand neighbors, such stellar encounters were more common in the early history of our solar system.
However, an interloping star is more likely to pull Planet Nine away completely and eject it from the solar system. Li and Adams find only a 10 percent probability, at best, of Planet Nine landing in its current orbit. Moreover, the planet would have had to start at an improbably large distance to begin with.
CfA astronomer Scott Kenyon believes he may have the solution to that difficulty. In two papers submitted to the Astrophysical Journal, Kenyon and his co-author Benjamin Bromley (University of Utah) use computer simulations to construct plausible scenarios for the formation of Planet Nine in a wide orbit.
“The simplest solution is for the solar system to make an extra gas giant,” says Kenyon.
They propose that Planet Nine formed much closer to the Sun and then interacted with the other gas giants, particularly Jupiter and Saturn. A series of gravitational kicks then could have boosted the planet into a larger and more elliptical orbit over time.
“Think of it like pushing a kid on a swing. If you give them a shove at the right time, over and over, they’ll go higher and higher,” explains Kenyon. “Then the challenge becomes not shoving the planet so much that you eject it from the solar system.”
That could be avoided by interactions with the solar system’s gaseous disk, he suggests.
Kenyon and Bromley also examine the possibility that Planet Nine actually formed at a great distance to begin with. They find that the right combination of initial disk mass and disk lifetime could potentially create Planet Nine in time for it to be nudged by Li’s passing star.
“The nice thing about these scenarios is that they’re observationally testable,” Kenyon points out. “A scattered gas giant will look like a cold Neptune, while a planet that formed in place will resemble a giant Pluto with no gas.”
Li’s work also helps constrain the timing for Planet Nine’s formation or migration. The Sun was born in a cluster where encounters with other stars were more frequent. Planet Nine’s wide orbit would leave it vulnerable to ejection during such encounters. Therefore, Planet Nine is likely to be a latecomer that arrived in its current orbit after the Sun left its birth cluster.
Finally, Li and Adams looked at two wilder possibilities: that Planet Nine is an exoplanet that was captured from a passing star system, or a free-floating planet that was captured when it drifted close by our solar system. However, they conclude that the chances of either scenario are less than 2 percent.
Li and Adams’ paper has been accepted for publication in the Astrophysical Journal Letters and is available online. Kenyon and Bromley have submitted their findings to the Astrophysical Journal in two papers available online: one on in-situ formation and one on gas-giant scattering.
Oysters are keystone organisms in estuaries around the world, influencing water quality, constructing habitat and providing food for humans and wildlife. Yet their populations in the Chesapeake Bay and elsewhere have dramatically declined after more than a century of overfishing, pollution, disease and habitat degradation. Smithsonian scientists and colleagues, however, have conducted the first bay-wide, millennial-scale study of oyster harvesting in the Chesapeake, revealing a sustainable model for future oyster restoration.
Despite providing food for humans for millennia, little is known about Chesapeake Bay oyster populations prior to the late 1800s. Using fossil, archaeological and modern biological data, the team of scientists was able to reconstruct changes in oyster size from four time frames: the Pleistocene (780,000–13,000 years ago), prehistoric Native American occupation (3,200–400 years ago), historic (400–50 years ago) and modern times (2000 to 2014).
They found that while oyster size fluctuated at certain points through time, it has generally decreased over time and the average size of modern oysters is significantly smaller than oysters from the 1800s and earlier.
“Our work demonstrates the importance of working across disciplines and using the past to help us understand and transcend modern environmental issues,” said Torben Rick, an anthropologist at the Smithsonian’s National Museum of Natural History and lead author of the research. “In this case, paleontology, archaeology, history and marine ecology all provided unique perspectives on the difficult puzzle of restoring Chesapeake oysters. Ultimately, they issue a challenge for us to make important and difficult decisions about how to restore and sustain our marine ecosystems and organisms.”
The team also found that Native Americans’ method of selecting and hand-collecting oysters likely resulted in more consistent average sizes and fewer very small individual oysters. People were likely removing oysters from the reefs in a way that was biased toward medium-sized oysters without decreasing the average size of the oysters in the harvested populations.
With limited variability in oyster size and abundance, and no strong evidence for a size decline from 3,500 to 400 years ago, the Native American Chesapeake Bay oyster harvesting appears to have been largely sustainable, despite changing climatic conditions and sea-level rise. The teams point to four supporting factors:
It is this sustainability of the Native American oyster fishery that can provide insight into the future restoration of oysters in the Chesapeake Bay and around the world. However, there are factors stacked against modern-day oysters that did not exist in the prehistoric Native American’s time.
“Chesapeake Bay oysters now face challenges resulting from disease, poor water quality and over a century of overfishing, which not only removes oysters, but also destroys the reef habitat oysters depend on,” said Denise Breitburg, co-author and senior scientist at the Smithsonian Environmental Research Center. “These factors have led to the decline of oysters in Chesapeake Bay and are making restoration difficult. But large-scale efforts are underway to try to reverse the trend.”
The team’s model of a sustainable prehistoric Native American harvest of oysters, primarily by hand from fringing reefs that left deeper-water reefs largely intact, supports recent plans for Chesapeake Bay oyster-restoration efforts. They include reduction of modern harvest levels and creation of increased no-take zones that are conceptually similar to deep-water areas where harvest was unlikely in Native American fisheries. Current restoration plans also include enhancement of oyster density using hatchery seed and the addition of new hard substrate where needed. The team’s Pleistocene data also provide a baseline against which the size distribution of oysters in no-take reserves could be evaluated.
While not solving all the challenges facing oysters in the Chesapeake, the team’s research provides an example of an apparently sustainable millennial-scale fishery, elements of which may help inform restoration and harvest in today’s ecosystem.
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For the first time, an egg laid by a female brown kiwi at the Smithsonian Conservation Biology Institute in Front Royal, Va., hatched May 10. The chick is the first for parents Ngati Hine Rua (female) and Ngati Hine Tahi (male). SCBI has previously hatched eggs originally laid at other zoos. Keepers will not know the sex of the chick for several weeks.
Ngati Hine Rua and Ngati Hine Tahi were given to SCBI as a gift from the government of New Zealand in 2010 after receiving a Maori blessing. Kiwi are sacred to the Maori people. The gift was the first time any kiwi had left New Zealand in 20 years. The Smithsonian’s National Zoo was the first outside of New Zealand to successfully breed kiwi in 1975. Feathers from kiwi at the Zoo and SCBI are repatriated to New Zealand and returned to the Maori people.
After Ngati Hine Rua laid the egg, Iwi, another male living at SCBI, incubated it for 30 days before keepers moved the egg to a meticulously climate-controlled incubator where it finished developing. Kiwi do not care for their chicks, which are capable of caring for themselves at birth. After hatching, the chick was moved to an incubator especially for newborn chicks. The chick appears to be healthy and doing well.
Kiwi, flightless birds similar in size to chickens, lay the largest egg-to-body-weight ratio of any bird. A kiwi egg is about 20 percent of the female’s size. Kiwi live in mated pairs and generally mate for life. The pair will defend a territory, which includes their nest. After females lay their eggs, they leave the egg with the male to incubate by himself. A chick will stay in its parents’ territory for up to one year, but is able to hunt and fend for itself from birth.
The nocturnal kiwi is endangered due to predators introduced to New Zealand by humans. Kiwi evolved without terrestrial mammal predators. Their biggest threats are dogs, cats and stoats introduced by humans.