USAP-DC

Notothenioid fishes live in the world's coldest marine waters surrounding Antarctica and have evolved strategies to avoid freezing. Past studies have shown that most Antarctic notothenioids produce special antifreeze proteins that prevent the growth of ice crystals that enter the body. While these proteins help prevent individuals from being killed by growing ice crystals, it is unclear how these fish avoid the accumulation of these small ice crystals inside their tissues over time. This project will observe how ice crystal accumulation relates to the harshness of the fish's habitat and the fish's behavior within different habitats of McMurdo Sound, Antarctica. The researchers will collect fishes and ocean observations at different field sites that cover a range of habitat severity in terms of temperature and iciness. Researchers will install an underwater ocean observatory near McMurdo Station which will include a HD video camera and hydrophone. The observatory will allow continuous monitoring of ocean conditions and fish behavior that will help explain the conditions and behaviors that contribute to the acquisition and accrual of ice inside the body. Acoustic and video data from the observatory will be available to other scientists and to the public. The project will advance understanding of the many challenges life faces in extreme cold environments. This work continues a line of inquiry that has resulted in the discovery of potential medical and food preservation applications. Hundreds of antifreeze protein (AFP) structure-function studies have been conducted in the laboratory, providing a basic physical understanding of the AFP-ice interaction. How AFPs function within fishes and their range of environments, however, is far from clear. This project will provide an understanding of notothenioid's freezing avoidance mechanisms, and strategies by quantifying the acquisition, accumulation, and loss of internal ice crystals. Specifically, the goal is to determine if and how habitat severity (as defined by iciness, seawater temperature, and prevalence of supercooled water) and fish behavior influence the abundance of ice crystals in their tissues. Four locations in the McMurdo Sound with different levels of habitat severity will be sampled for oceanographic conditions and ice crystal count within fish tissues. Researchers will use a new technique to count the number of splenic ice crystals, expanding on and simplifying previous methods. Environmental data loggers will be deployed for the duration of the project at the four sites to provide context and real-time assessment of environmental conditions. An oceanographic observatory near McMurdo Station will provide year-round, real-time and archival records of oceanographic conditions, in situ video observations of anchor ice growth and ice-organism interactions, hydroacoustic recordings, and serve as proof-of concept for expanding scientific infrastructure in McMurdo Sound related to monitoring of supercooled waters and oceanographic information.

Person	Role
Cziko, Paul	Investigator and contact
DeVries, Arthur	Co-Investigator

Antarctic Instrumentation and Support	Award # 1644196
Antarctic Organisms and Ecosystems	Award # 1644196

USAP-1644196_1

Deployment	Type
Paul Cziko	general deployment

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Long-Term broadband underwater acoustic recordings from McMurdo Sound, Antarctica (2017-2019)	None	exists
USAP-DC	Long-term underwater images from around a single mooring site in McMurdo Sound, Antarctica (2017-2019)	None	exists
USAP-DC	High-resolution nearshore benthic seawater temperature from around McMurdo Sound, Antarctica (2017-2019)	None	exists

1. Ainley, D., Cziko, P., Nur, N., Rotella, J., Eastman, J., Larue, M., et al.. (2020). Further evidence that Antarctic toothfish are important to Weddell seals. Antarctic Science, 1-13. (doi:10.1017/S0954102020000437)
2. Paul A. Cziko, Lisa M. Munger, Nicholas R. Santos, John M. Terhune; Weddell seals produce ultrasonic vocalizations. J. Acoust. Soc. Am. 1 December 2020; 148 (6): 3784–3796. (doi:10.1121/10.0002867)