A screenshot of the live-stream on Friday, June 21.

A screenshot of the live-stream on Friday, June 21.

This afternoon, MBL microbial oceanographer Julie Huber took an enthralled audience at MBL on a dive to the bottom of the sea, via a livestream video on YouTube. If you missed it, there are more opportunities to tune in this week!

Huber is part of an international team of scientists aboard research vessel R/V Falkor, operated by Schmidt Ocean Institute. The Falkor is spending June at the Mid-Cayman Rise, an ultraslow spreading ridge at one of the deepest points of the Caribbean Sea (about 4 miles down). At 6 AM ET/3 AM PT every day until June 29, the team will air live footage of their explorations along the ridge.

The team, which is led by Chris German of Woods Hole Oceanographic Institution, is focusing on two new hydrothermal vent fields, Europa and Walsh, during this expedition. These vents are cracks along the bottom of the ocean that form when the Earth’s plates shift. The scientists are studying the vents from biological, chemical, and physical perspectives to learn more about these dynamic geological formations and the extreme life they host.

Huber studies microbial life around the vents. She is interested in learning more about how the bacteria and Archaea can thrive in the harsh, hot conditions of the Mid-Cayman Rise. (Huber will continue this work on another Falkor cruise that she is leading this fall.)

The team uses an unmanned vehicle, HROV Nereus to explore the floor in-depth. Their live-stream video will be captured on the same cameras used by James Cameron’s DEEPSEA CHALLENGER submersible on its 2012 dive at the Mariana Trench.

Tune in tomorrow at 6 AM EST to the Schmidt Ocean Institute’s YouTube channel to watch the next Nereus dive live. (Dives may be delayed due to technical issues. Schedule updates are posted here.)

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By Aviva Hope Rutkin

Visiting scientist Guillermo Yudowski wants to make sea anemones happy.

Every morning, he arrives at his MBL laboratory and looks into a group of plastic tanks. Inside are samples of Aiptasia pallida, a hardy strain of anemone found in abundance near the University of Puerto Rico, where Yudowski conducts neurobiological research. Happy A. pallida, he says, are “colorful and open”; sad ones are closed and white. The white samples are near death and will only last three to four days in their containers.

Top view of a day-old spawned Porites spp. coral larvae. Composite image seen under a fluorescent microscope. Symbiotic zooxanthellae autofluorescence in red, larvae epidermis autofluorescence in green. Courtesy of Guillermo Yudowski.

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Turning white—becoming, in Yudowski’s words, “sad”—is called bleaching. The anemone’s tissues are home to zooxanthellae, vibrant photosynthetic algae that produce food for the anemone and give it a characteristic brown color. Bleaching expels this algae from their home. The bleaching process is thought to be triggered by stress: a decrease in light availability, for example, or changes in the water’s temperature or pH. And these changes don’t need to be dramatic. A difference of a couple degrees Celsius can be enough to effectively bleach an anemone.

Yodowski and his colleagues hope their research will point to a cost-effective treatment for bleaching, which poses a serious threat not only to anemones, but to the world’s coral reefs. Though anemones and corals are different, strategies that work for the one organism may be effective for another. The changing climate has already led to mass bleaching events in the Great Barrier Reef, as well as coral reefs in the Indian Sea, the Caribbean Sea, and the Florida Keys.

“If you read the literature, some say that all the coral is going to die in 50 years. Others say, maybe 50 to 100,” says Yudowski. “It doesn’t make a big difference.”

To move toward a solution, Yudowski wants to understand what’s happening to the anemones on a microscopic level. If we figure out why bleaching occurs on a cellular level, then perhaps we can discover how to stop it from happening altogether.

“We don’t really know much about the basic molecular mechanics of the process,” explains Yudowski. “We are trying to understand how stresses like increased ocean temperature and acidification induce the expulsion of the algae.”

Yudowski and his student, Michael Marty-Rivera, are treating anemones with antioxidant compounds found in red wine and green tea. Previous research shows that reactive oxygen species, a kind of chemically reactive molecule, can trigger the bleaching process. Yudowski and Marty-Rivera think that these antioxidants might be able to counteract the effects of these trigger molecules. They will test the efficacy of their treatments by measuring the amount of photosynthetic activity in the anemones, as well as the number of zooxanthellae present.

Yudowski and Marty-Rivera will spend two months at the MBL this summer before returning to the University of Puerto Rico where, in close collaboration with Professors Loretta Roberson and Joshua Rosenthal, they run several different coral research projects. They want to understand the mechanism of calcification in corals and how environmental variables, such as temperature and pH, impact corals’ ability to form reefs and maintain a healthy symbiosis with their zooxanthellae partners.

Funding for the research is provided by the Puerto Rico Center for Environmental Neuroscience and the National Science Foundation Center of Research Excellence in Science and Technology.

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.

 

Core sampling at Harvard Forest. Photo by KM Kowalski

An SJP fellow core sampling at Harvard Forest in 2012. Photo by KM Kowalski

 

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

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.

An  Arctic LTER greenhouse in peak autumn. Credit: Sadie Iverson

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.

 

 

 

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