Published In

Arctic, Antarctic, and Alpine Research

Document Type

Article

Publication Date

2013

Subjects

Glaciers, Sediments -- Geology, Bioavailability, Taylor Valley -- Antarctica

Abstract

Nutrient recycling occurs in hydrologically isolated cryoconite holes on the glaciers of the McMurdo Dry Valleys, Antarctica. Biogeochemical processes enrich the cryoconite holes with solute and nutrients compared to the source sediment and glacier ice. The position of the glacier within the landscape affects the physical and biogeochemical character of the cryoconite holes, with those found in more biologically productive areas of the valley having higher concentrations of C, N, and P and higher pH. Comprehensive assessment of the quality and quantity of bioavailable C, N, and P shows that the cryoconite holes represent a significant store of nutrient in this depauperate landscape, since the total mass of C and N is similar to that found in the ephemeral streams. The dissolved nutrients within the holes, and a significant proportion of the particulate store, are released to the valley ecosystem via the network of ephemeral streams and perennially ice-covered lakes as a result of hydrological connection with the supraglacial drainage system. In most cases, cryoconite holes are flushed every several years, but during warm periods which occur with near decadal frequency, all holes connect and flush their contents off the glaciers. Simple mass balance modeling shows that an increase in primary productivity observed in Lake Fryxell that followed such a melt event in 2001/2002 can be explained by an influx of nutrients (specifically N) generated in the cryoconite holes. These features are hence an integral part of the Dry Valley ecosystem and should be considered in models of downstream biological processes.

Description

Publisher's PDF reproduced here with author and publisher permission.

Originally published in Arctic, Antarctic, and Alpine Research, http://dx.doi.org/10.1657/1938-4246-45.4.440

Copyright 2013 Regents of the University of Colorado

DOI

10.1657/1938-4246-45.4.440

Persistent Identifier

http://archives.pdx.edu/ds/psu/10575

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