Thu 30 May 2013
Posted by Diana Kenney under MBL, Science Journalism Program
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Jim Motavalli, one of 12 journalists who recently spent 10 days in Woods Hole and at Hubbard Brook, NH, learning the ropes of ecosystems field science, reflects on his experience here. Jim took part in the Logan Science Journalism Fellowship program, which has been offered at the MBL since 1987.
An SJP fellow core sampling at Harvard Forest in 2012. Photo by KM Kowalski
Tue 28 May 2013
Posted by Diana Kenney under Program in Sensory Physiology and Behavior
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Some people prefer strong vertical lines in their clothing over horizontal ones, as they can appear slimming. As for cuttlefish? According to a new MBL study, when these marine creatures adaptively change their skin patterns for camouflage purposes, they respond to vertical visual cues in their environment more strongly than to horizontal cues.
A cuttlefish next to a checked wall pattern displays adaptive camouflage.
Photo courtesy of Kim Ulmer, MBL
The study, led by Kimberly Ulmer and Roger Hanlon in the MBL’s Program in Sensory Physiology and Behavior, is published in the April issue of the Biological Bulletin.
Many prior experiments have shown the influence of two-dimensional (2D) substrates, such as sand and gravel habitats, on camouflage, yet many marine habitats have three-dimensional (3D) structures, such as rocks and coral, among which cuttlefish camouflage from predators. In this study, Ulmer and Hanlon tested the relative influence of horizontal versus vertical visual cues on cuttlefish camouflage. They found that visual stimuli in the vertical dimension (2D or 3D) have a stronger influence on changeable camouflage than do 2D stimuli presented horizontally. This effect is noteworthy because in many of the experiments, the vertical stimuli represented only a small proportion of the total visual surrounds, indicating that cuttlefish are selectively responding to vertical cues.
Such choices highlight the selective decision-making that occurs in cuttlefish as they determine their camouflage body patterns.
Citation:
Ulmer KM, KC Buresch, MM Kossodo, LM Mathger, LA Siemann and RT Hanlon (2013) Vertical visual features have a strong influence on cuttlefish camouflage. Biological Bulletin 224: 110-118.
Fri 17 May 2013
Posted by ghebert under Ecosystems
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Arctic LTER greenhouses in peak autumn. Credit: Sadie Iverson
In 1989, MBL Senior Scientist Gaius Shaver and his colleagues set up a series of small experimental greenhouses on a hillside above the Toolik Field Station at the National Science Foundation Arctic Long Term Ecological Research site in northern Alaska. The clear plastic-covered greenhouses increase ambient soil temperatures by up to 2°C and are used by Shaver and other scientists to observe the effects of sustained warming on the Arctic environment. Today, the test plots are the longest-running climate warming study in the tundra.
New research from Seeta Sistla, a doctoral student at the University of California, Santa Barbara and a graduate of the Brown-MBL Partnership and Graduate Program in Biological and Environmental Sciences, her adviser, Josh Schimel, Shaver, and their colleagues reports the results the long-term warming experiment at the site.
The study reveals that decades of slow and steady warming have not changed the amounts of carbon in the soil, despite changes in vegetation and even the soil food web. Whether or not this phenomenon—no net loss of soil carbon despite long-term warming—is a transient phase that will eventually give way to increased decomposition activity and more carbon release, remains to be seen.
“This work demonstrates why long-term ecological research, and especially long-term whole-ecosystem experiments, are a good thing,” says Shaver. “The experiment on which this paper is based was set up in 1989, when Seeta Sistla was about 6 years old. There is no way she could have produced such a nice thesis if we had not set up these experiments so many years ago, not always knowing exactly how they would be used.”
The paper appeared in the May 15, 2013 Advance Online Publication of the journal Nature.
Other researchers participating in this study include John C. Moore and Rodney T. Simpson from Colorado State University, Fort Collins and Laura Gough from the University of Texas at Arlington.
Funding came from the National Science Foundation Long Term Ecological Research (LTER) Program, DOE Global Change Education Program Graduate Fellowship, a Leal Anne Kerry Mertes scholarship, and Explorer’s Club.
Mon 18 Mar 2013
Posted by Diana Kenney under MBL, Program in Sensory Physiology and Behavior
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Paloma T. Gonzalez-Bellido, who is now a postdoctoral scientist at the Marine Biological Laboratory (MBL), and colleagues from Howard Hughes Medical Institute, University of Minnesota, and Union College have been awarded a 2012 Cozzarelli Prize by the editorial board of Proceedings of the National Academy of Sciences (PNAS).
Gonzalez-Bellido and colleagues were honored for the “scientific excellence and originality” of their study of prey detection and interception in dragonflies.
The research was performed at Howard Hughes Medical Institute’s Janelia Farm Research Campus, where Gonzalez-Bellido was a postdoctoral scientist prior to joining the MBL’s Program in Sensory Physiology and Behavior in September 2011.
The study provides insight into basic visual-motor neural processing, and has implications for the development of “bioinspired” prosthetics for humans.
A green darner dragonfly, a member of the Aeshnidae family, in which Robert Olberg of Union College originally discovered the target-selective descending neurons (TSDNs). Credit: Brian Robert Marshall/Wikimedia
“I am honored to receive recognition for this work, for which we bridged the clinical and neuroethological fields, and developed new techniques,” says Gonzalez-Bellido. “This award has provided me with fuel to keep up the hard work and further my research plans.”
In order for a dragonfly to intercept its prey in midair (which dragonflies do with a 95% success rate), it needs to quickly track the prey and predict its future location. To understand how they undertake this complex task, Gonzalez-Bellido and her co-authors studied a small group of 16 motor neurons, called target-selective descending neurons (TSDNs), in the dragonfly Libellula luctuosa. These neurons, originally discovered by co-author Robert M. Olberg (Union College) in the green darner dragonfly, originate in the brain and extend to the thoracic ganglia, where the neural signal is interpreted and translated into wing muscle movements. Surprisingly, the scientists found that this small group of neurons can detect the direction of target prey with high accuracy and reliability across 360 degrees, and that this information is relayed from the brain to the wing motor centers in population vector form.
In 1988, co-author Apostolos Georgopoulos and his colleagues showed in monkeys that from the activity of neurons in the motor cortex, the population vector algorithm can predict the monkey’s upcoming arm movement. However, to achieve a more accurate prediction with this algorithm, upwards of 200 neurons were needed. Thus, the present discovery that a highly accurate neural code carrying information about target direction can be achieved with just 16 neurons is enlightening, and could have applications in the development of bioinspired robots. (Georgopolos is an MD-PhD at the University of Minnesota/Veterans Administration Medical Center who is interested in the development of prosthetics.)
Paloma Gonzalez-Bellido. Credit: HHMI/Janelia Farm
Randy Schekman, PhD, editor-in-chief of PNAS, describes the papers chosen for the Cozzarelli Prize as being “of exceptional interest… These papers are not merely technically superior but have had special impact and maybe novel techniques or novel applications of techniques, or very important discoveries.”
For this study, Gonzalez-Bellido and Trever Wardill (then at HHMI) developed a new protocol for labeling and confocal imaging of neurons in thick invertebrate tissue samples. In addition, her co-authors and former HHMI colleagues Hanchuan Peng and Jinzhu Yang developed a method for automatic 3D digital reconstruction (tracing) of neurons in microscopic images.
Gonzalez-Bellido sees the dragonfly as a promising model for understanding the evolution of neural systems. “It’s exciting that the same computation [the population vector algorithm] is used by monkeys and dragonflies for this task. Dragonflies belong to the most ancient groups of flying insects on earth, and they have changed little in 250 million years” she says.
The Cozzarelli Award was established in 2005 and named in 2007 to honor late PNAS editor-in-chief Nicholas R. Cozzarelli. Gonzalez-Bellido and the other awardees will be recognized at an awards ceremony during the National Academy of Sciences Annual Meeting on April 28, 2013, in Washington, D.C.
Out of more than 3,700 papers published in the journal last year, the editors selected Gonzalez-Bellido’s paper and five others for the Cozzarelli Prize.
Citation:
Gonzalez-Bellido PT, Peng H, Yang J, Georgopoulos AP and Olberg RM (2012) Eight pairs of descending visual neurons in the dragonfly give wing motor centers accurate population vector of prey direction. PNAS 110: 696-701 /doi/10.1073/pnas.1210489109
A PNAS commentary on the paper is here.
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Mon 11 Mar 2013
Posted by Diana Kenney under Ecosystems
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The U.S. Global Change Research Program (USGCRP) last week delivered its annual report to Congress for fiscal year 2013: Our Changing Planet.
The report highlights recent activities by 13 federal agencies to strengthen our scientific understanding of global changes including climate change, the threats and opportunities they present, and how they are likely to evolve over time.
In addition, Our Changing Planet showcases tangible results of work carried out by USGCRP agencies, including, for example, some of the most detailed, data rich maps of Alaskan permafrost ever generated; the most precise map ever produced of carbon stored in Earth’s tropical forests; critical information about the number and magnitude of extreme weather events in the United States; and updated maps that help gardeners and growers plan for harvesting seasons.
This report anticipates the USGCRP’s comprehensive Third National Climate Assessement, which will be released in early 2014. MBL Distinguished Scientist Jerry Mellilo chairs the advisory group that is preparing the National Climate Assessment, which presents the latest science about the current and projected effects of climate change across the United States.
The National Oceanic and Atmospheric Administration is announcing preliminary information that the U.S. experienced 11 disasters each costing over a billion dollars in losses in 2012. Of these 11 events, seven were severe weather or tornado events, and two were related to hurricanes/post tropical cyclones. The remaining two were the year-long drought and associated wildfires.