LAWRENCE — A study appearing in the journal PLOS ONE this week shows that bioluminescence — the production of light from a living organism — is more widespread among marine fishes than previously understood.
Most people are familiar with bioluminescence in fireflies, but the phenomenon is found throughout the ocean, including in fishes. Indeed, the authors show with genetic analysis that bioluminescence has evolved independently 27 times in 14 major fish clades — groups of fish that come from a common ancestor.
“Bioluminescence is a way of signaling between fishes, the same way that people might dance or wear bright colors at a nightclub,” said W. Leo Smith, assistant curator with the University of Kansas Biodiversity Institute, who co-authored the paper. He added that some fish also are thought to use bioluminescence as camouflage.
Smith said the huge variety in ways bony fish can deploy bioluminescence — such as leveraging bioluminescent bacteria, channeling light though fiber-optic-like systems or using specialized light-producing organs — underlines the importance of bioluminescence to vertebrate fish in a major swath of the world’s deep seas called the “deep scattering layer.”
“When things evolve independently multiples times, we can infer that the feature is useful,” Smith said. “You have this whole habitat where everything that’s not living at the top or bottom of the ocean or along the edges — nearly every vertebrate living in the open water — around 80 percent of those fish species are bioluminescent. So this tells us bioluminescence is almost a requirement for fishes to be successful.”
Indeed, the KU researcher said the most common vertebrate species on the planet lives within this habitat and is bioluminescent.
“The bristlemouth is the most abundant vertebrate on Earth,” Smith said. “Estimates of the size are thousands of trillions of bristlemouth fish in the world’s oceans.”
Smith and colleagues Matthew P. Davis of St. Cloud State University and John S. Sparks of the American Museum of Natural History found all fish they examined evolved bioluminescence between the Early Cretaceous, some 150 million years ago, and the Cenozoic Era.
Further, the team shows that once an evolutionary line of fish developed the ability to produce light, it tended soon thereafter to branch into many new species.
“Many fish proliferate species when they evolve this trait — they differentiate, but we don’t know why,” Smith said. “In the ocean, there are no physical barriers to separate groups of deep sea fishes, so why are there so many species of anglerfishes, for example? When they start using bioluminescence for species recognition, they diversify into a lot more species.”
To follow this line of inquiry, Smith and his co-authors now are working with a grant from the National Science Foundation to identify specific genes associated with the production of bioluminescence in fish.
In May, Smith and his two colleagues returned after taking a KU-chartered vessel to sea from the West Coast to collect samples of bioluminescent fish for analysis.
“We need fresh specimens for modern genetic approaches,” he said. “We’ll catch fishes and look at their mRNA to see what genes are being expressed. In the groups that produce their own light, we want to get the mRNA from the light organs themselves. With this information we can begin to trace the variation within the system, including the possibility of uncovering how this system evolved.”
- Brendan Lynch, KU News
Photos: A top, a Midshipman (Porichthys) emitting light from ventral photophores. Photo by Matt Davis. Top left, a preserved Black Dragonfish (Idiacanthus) with bioluminescent barbel. Photo by Matt Davis. Bottom left, a recently collected Deep-sea Hatchetfish (Sternoptyx) with bioluminescent ventral organs. Photo by Rene Martin.
Jennifer Stern, an undergraduate student mentored by Leo Smith, curator of ichthyology, is one of two students to be awarded the prestigious Udall Foundation Scholarship.
Stern and KU junior Ashlie Koehn were awarded the scholarship for 2015. They are among 50 students nationwide honored as 2015 Udall Scholars. The honor comes with a scholarship of up to $5,000 for the scholar's senior year. The Udall Foundation honors undergraduate college students across the nation for leadership, public service and commitment to issues related to American Indian nations or to the environment. KU’s University Honors Program worked with Koehn and Stern to apply for the highly competitive award.
Koehn, a junior from Burns triple-majoring in economics, environmental studies and global & international studies, plans a career in environmental economics.
Her interest was sparked not in Lawrence, but in Germany.
"A unique, clarifying moment came last summer while I was studying abroad with Environmental Studies in Freiburg, Germany," Koehn said. "There, Professor Earnhart taught a class on environmental economics, and I began thinking more deeply about the potential of economic policy as a way to protect the environment. I am currently studying economics in Kyrgyzstan because I see it as a way to make a difference on issues like climate change. I am incredibly honored to represent KU as a Udall Scholar and humbled by the faith and support shown in me."
"In Freiburg, Ashlie excelled academically and creatively exploited the many opportunities to explore issues relating to environmental economics and sustainability," said Dietrich Earnhart, professor of economics. "While many perspectives help to promote environmental sustainability, economics provides a useful framework for identifying the underlying causes of environmental problems and constructing effective policy solutions. Ashlie demonstrates that she has a great ability to apply this framework effectively in order to help solve current and future environmental problems."
Stern was one of 50 honorable mentions recognized by the Udall Foundation in 2014. After spending last summer at the New England Aquarium in Boston as a marine science summer camp intern, she was eager to apply again this year. Her focus in graduate school will be the effects of climate change on arctic ecosystems, specifically beluga whales.
"I am so incredibly grateful for the opportunities that the Udall Scholarship will provide me," said Stern. "I’m especially looking forward to the Scholar Orientation this summer, where I can meet and connect with others who are just as passionate about the environment as I am. I am dedicated to pursing research and connecting the public with nature, and I have pursued activities that have allowed me to do both. In addition, I have had the privilege of working with phenomenal research advisors who have shown me the possibilities and progress that research provides."
"Jenny’s ability to take the diverse research opportunities available to undergraduates at KU to build a directed research program toward her career goals exemplifies what makes Jenny and KU great," said Leo Smith, assistant professor of ecology & evolutionary biology who is directing Stern's independent honors research. "Jenny’s strength is in her creativity and her ability to connect ideas and synthesize across her experiences. I have been fascinated by her early recognition that a scientific leader must be able to conduct research, teach the next generation of scientists, and explain scientific findings to the public."
Smith was joined by Joy Ward, associate professor of ecology & evolutionary biology and another of Stern's research mentors, and Anne Wallen, assistant director of national fellowships and scholarships for the University Honors Program, at an impromptu surprise ceremony at the KU Natural History Museum to present Stern with the news of her Udall Scholarship. Koehn, who is spending the 2014-15 academic year in Bishkek, Kyrgyzstan, had a more intimate ceremony via Skype but was equally surprised by the news, which was delivered over a time difference of 12 hours.
Student applications include a summary of research, leadership and community service experience, as well as an 800-word essay on a speech, legislative act, book or public policy statement by former Arizona Congressman Morris K. Udall or former Arizona Congressman and Secretary of the Interior Stewart L. Udall, as well as three letters of recommendation addressing leadership, public service and academic achievements. Applications were submitted March 4.
More information about KU's 2015 Udall Scholars is below:
Ashlie Koehn, of Burns, is the daughter of Rodney and Carolyn Koehn and is a graduate of Fredrick Remington High School. She is a triple major in economics, environmental studies and global & international studies. She is a member of the Kansas Air National Guard; staff sergeant, 177th Information Aggressor Squadron; Kansas Air National Guard-cyber intelligence analyst/aggressor and was named the 2013 Kansas Air National Guard Airman of the Year. She is currently on leave while studying abroad in Bishkek, Kyrgyzstan, with Boren and Gilman scholarships. Koehn also is a member of the KU Global Scholars Program and was named a Newman Civic Fellow in 2014.
Jennifer Stern, of Lawrence, is the daughter of George and Joan Stern and is a graduate of Free State High School. She is majoring in ecology & evolutionary biology. She conducted original research on climate change and Ash trees with Joy Ward, associate professor of ecology & evolutionary biology, and on the evolution of venom across the sharks and stingrays with William Leo Smith, assistant professor of ecology & evolutionary biology and assistant curator at the Biodiversity Institute. Stern spent summer 2014 at the New England Aquarium Harbor Discoveries Camp as the marine science camp counselor intern. She is member of the University Scholar program and head peer leader for the Peer Led Undergraduate Supplements in Biology program. Stern received a 2014 Honorable Mention for the Udall Scholarship.
Source: KU News
Hannah Owens has been awarded an NSF Postdoctoral Research Fellowship in Biology in Competitive Area 2: Interdisciplinary Research Using Biological Collections. The project is entitled "Out of the Tropics and Out of the Drawer: Integrative Analysis of the Tropical Diversity Gradient From Museum Collections of New World Swallowtail Butterflies." The goal of the proposed research is to innovate in analysis of the tropical diversity gradient by incorporating traditionally-hypothesized drivers of the pattern, such as evolutionary history, clade age, and diversification rate, with novel factors such as tropicality of suitable ecological niche, breadth of abiotic niche, and morphological variability. I will be mentored by Rob Guralnick at the Florida Museum of Natural History at the University of Florida. The fellowship consists of $138,000 spread over two years.
Graduate student Sarah Gibson, itchthyology, has published research on the evolution of specialized, multidenticulate dentition in a Late Triassic fish from Utah, the oldest evidence of potential herbivory in ray-finned fishes. The paper came out early online access in the journal The Science of Nature: Naturwissenschaften.
Michelle Casey, who is a post-doc in the Division of Invertebrate Paleontology has just accepted a tenure track position at Murray State University in Kentucky. She will start there in the fall of 2015.
Graduate student Sarah Gibson's DDIG Proposal, "DISSERTATION RESEARCH: The Evolution of Specialized Teeth and Jaws in Early Mesozoic Ray-Finned Fishes and Their Impact on Widespread Niche Differentiation,” has been funded by the National Science Foundation. The PI for the grant is Hans-Peter Schultze, and co-PIs are Sarah Gibson and Paul Selden.
The ray-finned fishes (e.g., trout, clownfish, seahorse, bass) are the most diverse group of vertebrates on Earth today and display a vast array of physical differences with regard to body shape, skull and jaw morphology, and tooth specializations. Ray-finned fishes have a long evolutionary history, and this study focuses on two extinct groups of fishes that lived during the Early Mesozoic (250-190 million years ago): the disc-shaped, deep-bodied dapediids and the torpedo-shaped, primitive redfieldiids. These two groups of fishes provide an ideal contrast (e.g., deep body versus narrow body, differences in jaws) for testing hypotheses of the impact of specialization of tooth and jaw anatomy and morphology. The researches will compare this body shape contrast with the diet, habitat preference, behavior, and niche specialization of the fish. The project will study fossils from the Early Mesozoic, a volatile time in Earth's history with global tectonic events changing the geography of the planet and shaping the diversity of organisms in different ecosystems. This research will increase our understanding of how these two groups of extinct fishes have adapted to occupy different ecological spaces and exploit different food sources.
The research will utilize state-of-the-art two- and three-dimensional digital imaging techniques, such as micro-computed tomography (CT) scanning. These tools will measure jaw and cranial anatomy and morphology as well as tooth microwear, in well-preserved redfieldiid and dapediid fossils. Using these data the investigators of this project will be able to address hypotheses about how tooth and jaw morphology relate to ecological niche space and evolutionary history. This project will provide graduate and undergraduate training in morphological and morphometric techniques, and data obtained from this study will be catalogued in online data repositories.
Brendan Lynch from the Office of Public Affairs recently interviewed Matt Davis and Leo Smith from KU Biodiversity Instutute’s Ichthyology for a research feature on ku.edu concerning their three-year, $575,000 grant from the National Science Foundation. With the grant, they will study evolutionary patterns and diversity in three lines of widespread deep-sea fishes: lizardfishes, lanternfishes and dragonfishes.
Matt Davis, Nancy Holcraft, Ed Wiley, Leo Smith and John Sparks, have learned that their research paper, "New Study Links Species Specific Bioluminescence with Increased diversification in open ocean," has been published in the journal Marine Biology.
From the American Museum of Natural History news release: “Scientists have shown for the first time that deep-sea fishes that use bioluminescence for communication are diversifying into different species faster than other glowing fishes that use light for camouflage. The new research indicates that bioluminescence—a phenomenon in which animals generate visible light through a chemical reaction—could promote communication and mating in the open ocean, an environment with few barriers to reproduction."
Though present in more than 6,000 living species of fish, the adipose fin, a small appendage that lies between the dorsal fin and tail, has no clear function and is thought to be vestigial. However, a new study analyzing their origins finds that these fins arose repeatedly and independently in multiple specie
The research of Leo Smith and Matt Davis of the Biodiversity Institute has been published this week. Links to the NY Times article, with video, is below, along with other links reporting about the research:
Original article in PLOSone:
National Geographic News:
World Science Festival blog: