Marine biologist Mackenzie Gerringer studies the depths of the world’s oceans from the rolling hills of Geneseo.
By Robyn Rime
Down in the oceanâs trenches â far beyond the reach of sunlight â the deep sea is unimaginably dark, a world of frigid temperatures and immense pressures. Marine organisms manage to flourish in these harsh environments, and assistant professor of biology Mackenzie Gerringer studies how.
âI fell in love with the mystery of deep-sea habitats and was struck by how little we understand about them,â she explains. âThat sense of discovery kept me exploring deeper and deeper, all the way to the bottom.â
So little is known about deep-water environments that almost every expedition uncovers something new. Gerringer, who earned a doctorate in marine biology from the University of Hawaiâi at MÄnoa discovered a new species with colleagues from the University of Hawaiâi and Newcastle University, which they described in 2017. The deepest living fish in the oceans, it was found in the Mariana Trench in the western Pacific near Guam, where waters run deeper than Mt. Everest is tall.
âThis fish lives deeper than any known vertebrate,â says Gerringer, âso finding it was very exciting.â
As an animal physiologist, Gerringer specializes in the life histories, feeding mechanisms and high-pressure adaptations that help deep-sea fishes survive in the oceanâs trenches. Her most recent paper examines high-pressure tolerances in deep-sea fish enzymes (The FEBS Journal, 6 April 2020).
âPressures in the deep sea are very high. At the bottom of the Mariana Trench, pressures reach 15,000 pounds per square inch, about the equivalent of an elephant standing on top of your thumb,â Gerringer says. âIâm interested in how fish thrive under that high pressure.â
Gerringerâs lab at Geneseo is examining that and other questions, such as how other organisms survive high pressures, how long they live, what they eat and how they interact. Such research is possible even at land-locked Geneseo in part because, as Gerringer points out, ânone of us live in the deep seas. We go to sea, take collections, then come back to the lab to do our analyses,â and in part because of the collaborative nature of deep-sea biology, which requires considerable resources.
Students in Gerringerâs lab are working on potentially describing three new species of deep-water snailfish by examining samples collected by colleagues from the University of Hawaiâi at Ma-noa and the Monterey Bay Aquarium Research Institute. Small, tadpole-shaped snailfish species live around the planet, from intertidal zones to the deepest trenches. CT scans of the samples and examination under a microscope allow students to look minutely at the snailfishesâ bodies, or morphologies, and DNA sequencing will help them build genetic trees showing relationships to previously known species.
âWe need both morphological and genetic evidence to describe a new species,â explains Gerringer. âIf theyâre new, weâll be able to name them and publish a species description. But even if they arenât new species, the students have had the chance to understand taxonomy, examine DNA sequences, take accurate measurements and learn 3D data processing.â
âAdding to the understanding of biodiversity present in the deep oceans has been incredible,â says biology major Jessica Palmeri â21. Adds Brett Woodworth â22, also a biology major, âItâs an unusual opportunity to potentially play a part in discovering new species of fish.â
Exploring the oceanâs mysteries â as vital as that goal may be â is, in the end, only part of Gerringerâs intention. âI hope students can find a connection to the oceans and to deep-sea habitats that makes them feel a link with and responsibility for these vital and amazing ecosystems on our planet,â she says.
