Commonly known as “electric flame scallops” or “disco clams”, the Ctenoides ales organism produces a flashy light display that is unique among bivalve mollusks. By rolling and unfurling an iridescent lip, the disco clam creates a strobe effect of blue light, whose mechanism had previously been unknown.
Berkeley graduate student Lindsey Dougherty studies the disco clams and her research recently caught the attention of national media after she presented her findings at the Society for Integrative and Comparative Biology annual meeting.
Disco clams (Ctenoides ales) live in small crevices at up to 20m below the ocean’s surface.
Dougherty’s research determined that the light display is a result of reflective tissue that is only present and visible on the clam’s unfurled mantle tip. Surface Optics loaned a SOC710-VP hyperspectral imager to Dougherty and Berkeley’s Caldwell Lab to use in her continuing research into the mechanics and behavioral purpose behind the disco clam light show. Dougherty was kind enough to answer a few questions about how she applied the SOC710-VP to her work:
What got you most excited when saw the first hyperspectral image(HSI) of a Disco Clam produced by the SOC710-VP?
Dougherty: When I saw the first HSI of the disco clam, I was most excited by how easy it was to navigate various parts of the tissue and see the resulting differences in reflectance simply by moving the cursor throughout the image. For my Disco Clams specifically, I never realized how important the transitional change was from the red-shifted mantle tissue to the blue-shifted reflective edge (the “Disco” part) when doing point measurement spectrometry. By exploring various pixels within the HSI image however, I was able to show that the transition was gradual, which gives me crucial insight into structural components of the tissue and the reflecting cells, and can be compared with my transmission electron microscopy data.
What are some of the spectral features that you are looking for?
Dougherty: Spectral features that are most useful are those that are important in a biological context, such as percent reflectance or irradiance. One of the most useful things about the HSI is that a photo can be taken in a given environment and every part of the image can be analyzed, allowing the opportunity for abiotic and biotic comparisons and capturing an immense amount of spectral data.
What are the benefits of using hyperspectral imaging in your research with the Disco Clam?
Dougherty: One benefit of using HSI with the Disco Clams is that I’m able to take an image of a large portion of tissue or of the entire organism, which is important given how variable the ocean’s photic environment can be. The HSI would be much easier to alter environmental conditions, such as the amount of ambient light available for reflection, and see how those changes affect different portions of the tissue, and whether those changes are uniform or if there is a greater effect in different morphological spaces.
A closer look at the disco clam’s reflective mantle edge. Hyperspectral imaging can allow researchers to collect new data on this reflective tissue.
Do you see this technology being applied to other marine biology applications?
Dougherty: Light is incredibly important in the ocean, whether it’s pigment or structurally based coloration, camouflage, reflectance, fluorescence or bioluminescence. The uses of color and light are incredibly important in intra and interspecific communication, so understanding more about the properties of the light in an environmental context is an important step to understand how the signals are produced and perceived. The ability to capture an image of the entire organism as well as it’s surroundings is a huge step forward in this analysis. I suppose the next step is to get some waterproof housing!
How much of a difference did it make using a hyperspectral imager as apposed to a point measurement spectrometer?
Dougherty: The HSI is superior to a point measurement spectrometer in looking at transitions between reflectance spaces. Additionally, having a single image of the entire tissue or organism eliminates the possibility of changes in external conditions, which can occur between single shots using a point measurement spectrometer. It also drastically reduces the amount of time and effort that go into collecting data, as a single picture will give data for every single pixel. The power of that tool contributes exponentially to data acquisition and comparative analysis.