Exploring Antarctica’s acoustics with leading wildlife researchers
It’s well known that Antarctica is absolutely bursting with jaw-dropping sights, but what about the sounds of this otherworldly environment? During your Hondius adventure, you can enjoy interactive workshops led by leading scientists who will show you there’s just as much in Antarctica to amaze the ears as the eyes.
The science of sounds
The main purpose of our acoustics workshop is to record and analyze the sounds made by Antarctic animals, both above the waves and below them. The animals we may record include whales, seals, penguins, and seabirds. With whales, for example, we can use hydrophones (underwater microphones) that we lower into the water. We can also use our Zodiac boats to get closer to the whales and deploy one or two hydrophones over the side. Our hydrophone holders can even hold underwater video cameras to capture the animals if water clarity and local conditions permit.
Various means of recording below and above the water
We can record underwater sounds using special amplifiers coupled to analogue-to-digital converters, recording the digital signals directly to a laptop. The recording system can cover the low frequencies used by large baleen whales, like fin and humpback whales, as well as the ultrasonic clicks used by killer whales and dolphins. We can hear the ultrasonic clicks of dolphins by playing them through a special detector that converts high frequency signals to our hearing range. For recording video signals as files on a laptop (Mac or Windows), we use video recorder software like Elgato Video Capture. The same setup can be used to record the underwater sounds of seals, if we’re lucky. We can also record the sounds of penguins and seabirds using a handheld sound recorder that stores these sounds digitally. Video cameras can also be used to record vocalizations and visual images for later analysis.
Analyzing Antarctic sounds
To analyze our sound files, we use free analysis software like Audacity and R (for those who would like to design their own analysis programs). Of interest to us is the frequency structure of our recorded sounds (or calls), the relative amplitude (loudness) of calls, the time duration of calls, and the call rate. If we use two hydrophones attached to a rod, we can get an indication of the bearing to the whale, either horizontally (to the right or left of our setup) or vertically (toward the surface or deeper). To analyze video files, we use iMovie (Mac) or Windows Movie Maker. We can speed up or slow down the video recordings or add our audio recordings to the video soundtrack. If the sounds come from a dolphin, we can slow these down to our hearing range with the sound analysis software or use an ultrasonic detector to hear a facsimile of the sounds in real time. These detector sounds can be clipped to the corresponding video recording, if available.
Marianne H. Rasmussen
Marianne is currently a research professor at the University of Iceland’s research center in Húsavík. She has her master’s degree and Ph.D. from Odense University (now the University of Southern Denmark – SDU) in Denmark. She went on a Danish expedition cruise, Galathea3, from Nuuk, Greenland, to Freemantle, Australia, on the project called Sounds in the Ocean. She was a cruise leader on aerial surveys in Greenland on large whales and narwhals. She has been involved in research projects about whales in Sri Lanka and Hawaii, and about dolphins in New Zealand. Her research projects are mostly about sound, communication, or behavior in cetaceans. Currently she is involved in projects about blue whales, humpbacks, killer whales, white-beaked dolphins, and harbor porpoises. She was a visiting scholar to Woods Hole Oceanographic Institution in the United States and is a co-PI on a project about hearing in auks, where the hearing of puffins was measured in Iceland. She teaches a marine mammal field course in Húsavík through the University of Iceland every summer with students from all around the world.
Ole Næsbye Larsen, Ph.D.
Since 2018, Ole has been an associate professor emeritus at the University of Southern Denmark’s (SDU) Department of Biology in Odense. He received his Master’s Degree in Zoology from Copenhagen University, and after studying animal behaviour at Queen’s College, Oxford University, he received his Ph.D. in Sensory Biology from Odense University in 1980. Shortly after that, he was employed as associate professor at SDU. He has been based at SDU ever since, interrupted only by sabbaticals at overseas universities (University of Queensland, Australia; University of Maryland College Park, USA; Queen’s University, Canada; University of California Santa Cruz, USA; Indian Institute of Science, Bangalore India) and several field projects in Costa Rica, Mozambique, and Colorado. He is specialized in bioacoustics, working on the mechanisms of sound production and hearing in animal species ranging from water beetles and crickets to parrots and walruses. Lately he has studied underwater hearing in seabirds, mainly in Iceland.
Lee A. Miller
Lee is currently professor emeritus at the Institute of Biology, University of Southern Denmark, in Odense. He has a master’s degree and Ph.D. in Biology from Harvard University. He has had a NATO postdoctoral fellowship to study the sensory physiology of hearing in locusts at the University of Copenhagen, after which he went to the University of Kentucky as an assistant professor in biology. Following this, he accepted a position at the Institute of Biology, Odense University (later the University of Southern Denmark), as associate professor. He took two sabbaticals in the US, one at Stanford University and the other at Brown University. His main research covers hearing and sound production in insects, bats, and toothed whales. Most of his studies center on echolocation in bats and toothed whales. His latest publication concerns the evolution of hearing and sound production in several species of small-toothed whales, including harbor porpoises.
Sara Torres Ortiz
Sara is a researcher at the University of Southern Denmark, where she finished her Master’s Degree in Animal Behavior and Bioacoustics in 2016. She is originally from Spain, where she completed her MSc studies in oceanography at the University of Cadiz. As a researcher, Sara is involved in many different research projects involving animal behavior and bioacoustics, both in the field and in the lab. When she first arrived in Denmark, she helped train a group of grey seals and cormorants participating in hearing and cognition tasks. With Montpellier University, she has investigated the sensory abilities of whales in Spain and Iceland. Currently she studies the behavior and communication of wild harbor porpoises using drones.
Sara is an experienced guest lecturer and teaching assistant at the University of Southern Denmark.