LTER: MCM6 - The Roles of Legacy and Ecological Connectivity in a Polar Desert Ecosystem

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

The McMurdo Dry Valleys (MDVs) LTER seeks to understand how differences in long-term environmental variability interact with persisting landscape conditions to alter the structure and functioning of this extreme polar desert ecosystem. The organisms in this ecosystem are generally tiny. Bacteria, small invertebrates, cyanobacterial mats, and algae can be found across the streams, soils, glaciers, and ice-covered lakes. These organisms have adapted to the cold and arid conditions that prevail outside of lakes for all but a brief period in the austral summer when the ecosystem is connected by meltwater. Most biological activity occurs in the summer when air temperatures rise barely above freezing, soils warm and glacial meltwater flows through streams into the open moats of lakes. Over the past 30 years, the MDVs have been affected by cooling, heatwaves, floods, rising lake levels, as well as permafrost and lake ice thaw. This project seeks to understand the role of past events and conditions combined with current physical and biological interactions in shaping the current ecosystem. Four questions will be addressed, related to 1) whether specific organisms are indicative ecosystem stability, 2) how past events influence current ecosystem resistance to big changes, 3) whether times of high activity help to maintain later ecosystem stability, and 4) how changes in disturbances may impact ecosystem persistence through the winter. This project also contributes an important educational and outreach function by providing immersive research and educational experiences that include students and artists. This helps to ensure a well-trained next generation of researchers in polar science and communicates the importance of Antarctic ecosystem stewardship. In this iteration of the McMurdo LTER project (MCM6), the project team will test ecological connectivity and stability theory in a system subject to strong physical drivers (geological legacies, extreme seasonality, and contemporary climate change) and driven by microbial organisms. Since microorganisms regulate most of the world’s critical biogeochemical functions, these insights can be relevant beyond polar ecosystems and can inform understanding and expectations of how natural and managed ecosystems respond to ongoing environmental variation. MCM6 builds on previous foundational research, both in Antarctica and within the LTER network, to consider the temporal aspects of connectivity and how it relates to ecosystem stability. The project team hypothesizes that the structure and functioning of the McMurdo Dry Valleys ecosystem is dependent upon ecosystem legacies and the contemporary frequency, duration, and magnitude of ecological connectivity. This will be tested with new and continuing monitoring, experiments, and analyses of long-term datasets to examine the stability of these ecosystems as reflected by sentinel taxa, the relationship between legacies and resilience, the importance of material carryover during periods of low connectivity to maintaining biological activity and community stability, and how changes in disturbance dynamics disrupt ecological cycles through the polar night. MCM6 will also continue its mission of training and mentoring students, postdocs, and early career scientists as the next generation of leaders in polar ecosystem science and stewardship. Building on past success, collaborations will be established with teachers and artists embedded within the science teams, who will work to develop educational modules with science content informed by direct experience and artistic expression. Undergraduate mentoring efforts will incorporate computational methods through a new data-intensive scientific training program for REU students. The project will also establish an Antarctic Research Experience for Community College Students at CU Boulder, to provide an immersive educational and research experience for students in community colleges. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.