Publikationsdatum:
2016-02-11
Beschreibung:
Streams in the McMurdo Dry Valleys (MDVs) of Antarctica moderate an important hydrologic and biogeochemical connection between upland alpine glaciers, valley-bottom soils, and lowland closed-basin lakes. Moreover, MDV streams are simple but dynamic systems ideal for studying interacting hydrologic and ecological dynamics. This work synthesizes 20 years of hydrologic data, collected as part of the McMurdo Dry Valleys Long-Term Ecological Research project, to assess spatial and temporal dynamics of hydrologic connectivity between glaciers, streams, and lakes. Long-term records of stream discharge (Q), specific electrical conductance (EC), and water temperature (T) from 18 streams were analyzed in order to quantify the magnitude, duration, and frequency of hydrologic connections over daily, annual, and inter-annual timescales. At a daily timescale, we observe predictable diurnal variations in Q, EC, and T. At an annual timescale, we observe longer streams to be more intermittent, warmer, and have higher median EC values, compared to shorter streams. Longer streams also behave chemostatically with respect to EC, whereas shorter streams are more strongly characterized by dilution. Inter-annually, we observe significant variability in annual runoff volumes, likely due to climatic variability over the 20 record years considered. Hydrologic connections at all timescales are vital to stream ecosystem structure and function. This synthesis of hydrologic connectivity in the MDVs provides a useful end-member template for assessing hydrologic connectivity in more structurally complex temperate watersheds. This article is protected by copyright. All rights reserved.
Print ISSN:
0885-6087
Digitale ISSN:
1099-1085
Thema:
Architektur, Bauingenieurwesen, Vermessung
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Geographie
