Autonomous Year-Round Sampling and Sensing to Explore the Physical and Biological Habitability of Permanently Ice-Covered Antarctic Lakes

Abstract

A B S T R A C TThe lakes of the McMurdo Dry Valleys, Antarctica, are some of the only systems on our planet that are perennially ice-covered and support year-round metabolism. As such, these ecosystems can provide important information on conditions and life in polar regions on Earth and on other icy worlds in our solar system. Working in these extreme environments of the Dry Valleys poses many challenges, particularly with respect to data collection during dark winter months when logistical constraints make fieldwork difficult. In this paper, we describe the motivation, design, and challenges for this recently deployed instrumentation in Lake Bonney, a lake that has been the subject of summer research efforts for more than 40 years. The instrumentation deployed includes autonomous water, phytoplankton, and sediment samplers as well as cable-mounted profiling platforms with dissolved gas and fluorometry sensors. Data obtained from these instruments will allow us, for the first time, to define the habitability of this environment during the polar night. We include lessons learned during deployment and recommendations for effective instrument operation in these extreme conditions.

Photoadaptation to the polar night by phytoplankton in a permanently ice-covered Antarctic lake

“…The extreme logistical constraints during the Antarctic winter make field activities during this time virtually impossible. Autonomous year‐round sampling and sensing instrumentation have been recently deployed in Lake Bonney (Winslow et al ) which will help define the habitability of these extreme aquatic systems during the polar night. Incorporation of real‐time measurements of microbial community dynamics during the winter as well as an improved appreciation for alternative autotrophic contributions to energy and carbon inputs will be critical in assessing climate‐associated shifts in microbial community functioning of these unique and sensitive ecosystems.…”

The physical limnology of a permanently ice‐covered and chemically stratified Antarctic lake using high resolution spatial data from an autonomous underwater vehicle

“…Briefly, ENDURANCE was deployed through an ∼ 2 m diameter hole created in the perennial ice cover using standard drilling and melting techniques (Winslow et al ). The vehicle executed a grid survey, with grid points being approximately 100 m apart (Fig.…”

The unique methodological challenges of winter limnology

“…Winter research to date has largely been the purview of polar investigators (e.g., Greenbank ; Winslow et al ), but interest is increasing. In 1996, a National Research Council report set forth two fundamental questions that have yet to be fully addressed (McKnight et al ), and have grown in relevance as ice cover duration shortens worldwide (Magnuson et al ): what are the critical events and conditions that control autotrophic and heterotrophic processes during winter, and what critical winter processes control the behavior of ecosystems in the subsequent spring and summer?…”