MBL, WOODS HOLE, MA—From the mysteries of comb jelly propulsion to the potential health effects posed by last year’s oil spill in the Gulf of Mexico, scientists at the Marine Biological Laboratory (MBL) are exploring some fascinating and important phenomena this summer.
Summer on Cape Cod is synonymous with a surge of tourists, but also a surge of visiting scientists at the MBL. For more than a century, researchers have come to the MBL each summer from around the world to immerse themselves in biological discovery. Researchers enjoy the collaborative atmosphere, the access to advanced imaging equipment and expertise, and the escape from academic duties at their home institutions. Here is a sampling of some of the research underway this summer at the MBL’s Whitman Center for Research and Discovery:
A New Underwater Video Camera Opens Window into the Behavior of Jellies
MBL Whitman Center researchers are testing a new underwater video camera system that will allow scientists to study the propulsion and behavior of jellies in their natural habitat.
In the lab, you can get a sense for how a jelly swims and captures its prey, explains Sean Colin, a marine ecologist at Roger Williams University, who helped to develop the system, called a self-contained underwater velocimetry apparatus, or SCUVA for short. But what’s missing is the influence that ocean currents, nearly impossible to accurately mimic in an artificial setting, have on these processes. “That’s what we need this system to answer,” says Colin. “How important is this natural background flow to determining who they feed on and how much they’re able to ingest?”
This summer, Colin, along with colleague John Costello, a biology professor at Providence College, will use the SCUVA to observe the warty comb jelly, a native species in plentiful supply in the waters off the coast of Woods Hole, Massachusetts. “Primarily what we’re interested in is understanding how jellyfish and ctenophores (like these comb jellies) interact with their surrounding fluid, because that influences how they swim, who they eat and, ultimately, their impact on the ecosystem,” says Colin. “The SCUVA is allowing us to do that.”
Divers John Costello (L) and Kakani Young (R) test the SCUVA system off of Friday Harbor in Puget Sound, Washington. Credit: Eric Klos
The camera is on the left with the laser shown on the right. The system uses a laser beam, fitted with optics that flatten the beam into a paper-thin sheet, to illuminate a single layer of the free-floating natural particles found throughout the ocean. When a jelly moves through the flattened beam, a high-definition camera captures what is essentially a cross-section of the animal, displacing the particles as it swims. Click for larger image. Credit: Kakani Young
Video Credit: Amanda Martinez
Collecting Water Samples.jpg: Tar balls float near this Conductivity, Temperature, Depth (CTD) rosette, used to collect water samples from the Gulf of Mexico during the oil spill. Credit: NOAA
A pod of striped dolphins swims through surface oil from the spill. New research examines the effect that compounds in the oil may have on animal development. Credit: NOAA
Oil Near the Spill Source.jpg: Response boats at the site of the Deepwater Horizon oil spill on May 20, 2010. Credit: NOAA
Does Oil from the Deepwater Horizon Spill Affect Animal Development?
More than a year since BP’s Deepwater Horizon oil rig exploded and sank, leaking nearly five million barrels of crude oil into the Gulf of Mexico, questions still linger as to the potential effect the oil may be having on the Gulf ecosystem and human health.
This summer, Diane Heck, an MBL Whitman Center researcher and chair of the Department of Environmental Health Science at New York Medical College, is investigating whether phenolic compounds in the oil may be capable of causing developmental effects in mammalian cells.
Heck is working with two types of samples from the Gulf of Mexico: oil obtained directly from BP’s fractured wellhead and aged oil collected from the water’s surface, which is expected to contain chemical dispersants used to clean up the spill. The samples were provided by collaborators at Louisiana State University and the Environmental and Occupational Health Sciences Institute (EOHSI), a joint institute between Rutgers University and the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School.
Heck aims to identify specific molecular pathways in the mammalian cells that are being altered by the phenolic compounds within the oil. Phenolic compounds have been shown to mimic hormones crucial to the human body’s development. Preliminary testing has revealed that the samples affect gene expression in epithelial cells, as well as cells that play a critical role in the early formation of the kidneys.
Ultimately, the research would help to inform exposure assessments. “It gives us a way of knowing that whatever is in this water, which may look just fine or not fine, is causing biological events,” says Heck. “But it’s going to take a lot of work at the molecular and biological levels,” she cautions. “At this point, we’re just laying the groundwork to start putting that together.”
Female midshipman fish use their sense of hearing to guide them to potential mates. Credit: Amanda R. Martinez
Whitchurch points out a male midshipman fish in its fictitious nest in a monitoring tank. Credit: Amanda R. Martinez
Whitchurch is using this new telemetry tag to remotely monitor how sound is processed in the brain of free-swimming plainfin midshipman fish. Credit: Allen Mensinger
AUDIO:
Male Midshipman Hum: MP3 Format
A 28-sec audio clip of the low-frequency, resonant hum that Type 1 male midshipman fish use to attract females to their nests. Credit: Elizabeth Whitchurch
New Telemetry Tag May Reveal How Singing Fish Encode Underwater Sound
A new tracking device capable of wireless data transmission is allowing MBL scientists to explore how sounds are processed in the brain of free-swimming fish. The device, a type of telemetry tag, was developed by Whitman Center researcher Allen Mensinger, and is being used by fellow researcher Elizabeth Whitchurch to study the plainfin midshipman, a nocturnal toadfish that lives off of the Pacific coast of North America.
Sound plays a crucial role in reproduction for the plainfin midshipman. At night, during the breeding season, males attract potential mates by emitting a low-frequency hum. Because it is dark, this hum must act as a map, guiding interested females to the males’ nests where they then lay their eggs. The process that scientists are hoping to better understand is how exactly the female midshipman brain turns these sounds into directions that lead the fish to the male’s location.
Due to limitations of the tools used to monitor fish neurons, previous research has focused only on immobilized fish, reacting to recorded calls piped in via speaker to a tank roughly the size of a five-gallon bucket. But using this new, telemetry tag along with other novel methods, Whitchurch hopes to be able to measure how the midshipman brain encodes sound as multiple fish swim freely, responding to each other’s live calls, in a tank about the size of a kids’ plastic swimming pool.
“The stimulus,” says Whitchurch, referring to the midshipman’s call, “is going to be conceivably changing for the fish as it turns its body from one direction to the next. So we want to know: What is it about the physical stimulus that’s being encoded in the brain as the fish moves through the water?” Understanding this process, she explains, could potentially inform the design of future mobile electronic devices that would use sound to navigate underwater.
Whitchurch, a 2011 Grass Fellow at the MBL, is a postdoctoral scientist at the University of Washington. Mensinger is a professor at the University of Minnesota Duluth.
Sea Lamprey Mouth GLFC: Credit: Great Lakes Fishery Commission
Whitman Center investigators Jennifer Morgan (L) and Ona Bloom (R) next to a tank of lampreys in their lab at the Marine Biological Laboratory, Woods Hole . Credit: Amanda R. Martinez
A close-up of neurons in the lamprey brain. Lampreys have super-sized neurons that can range from ten to 20 times larger than mammalian neurons. The rightmost chart shows the neurons that are capable of regenerating, labeled in black. Click for larger image. Credit: Jennifer Morgan
Sea Lampreys May Hold Insight to Understanding Nerve Cell Regeneration
Scientists have reported since the 1950s that the sea lamprey, an aquatic animal with an eel-like body and a gaping mouth full of concentric rows of teeth, can regenerate its spinal cord after severe injury and recover the ability to swim. The question since has been: How do they do this?
A team of MBL Whitman Center researchers has been investigating the answer. This summer, Ona Bloom, Jennifer Morgan, and Joseph Buxbaum are charting a timeline of the changes that occur as lampreys progress through the wound healing and regeneration processes after spinal cord injury. The group is collaborating with Joel Smith of the MBL's Bell Center for Regenerative Medicine and Tissue Engineering.
Using state-of-the-art DNA sequencing, the researchers will capture and investigate all of the molecular changes that accompany the recovery process and attempt to relate that information to observed changes at the cellular level. This information will also be correlated with changes in the animal's behavior, as it regains its ability to swim.
“One of the key questions is: What makes one cell regenerate while another one doesn't and dies?” says Morgan.
“If we can figure out the recipe that nature is already using to accomplish successful regeneration, the hope is that we can then use that information to try and help mammalian neurons have similar success in regenerating,” says Bloom.
Bloom is an assistant investigator at the Feinstein Institute for Medical Research and assistant professor at the Hofstra North Shore-LIJ School of Medicine, Morgan is an assistant professor at the University of Texas at Austin, and Buxbaum is a professor at Mount Sinai School of Medicine.
-- Written and produced by Amanda Rose Martinez
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The Marine Biological Laboratory (MBL) is dedicated to scientific discovery and improving the human condition through research and education in biology, biomedicine, and environmental science. Founded in 1888 in Woods Hole, Massachusetts, the MBL is an independent, nonprofit corporation.
