The aeolian flux of calcium, chloride and nitrate to the McMurdo Dry Valleys landscape: evidence from snow pit analysis

We have determined the flux of calcium, chloride and nitrate to the McMurdo Dry Valleys region by analysing snow pits for their chemical composition and their snow accumulation using multiple records spanning up to 48 years. The fluxes demonstrate patterns related to elevation and proximity to the ocean. In general, there is a strong relationship between the nitrate flux and snow accumulation, indicating that precipitation rates may have a great influence over the nitrogen concentrations in the soils of the valleys. Aeolian dust transport plays an important role in the deposition of some elements (e.g. Ca2+) into the McMurdo Dry Valleys' soils. Because of the antiquity of some of the soil surfaces in the McMurdo Dry Valleys regions, the accumulated atmospheric flux of salts to the soils has important ecological consequences. Although precipitation may be an important mechanism of salt deposition to the McMurdo Dry Valley surfaces, it is poorly understood because of difficulties in measurement and high losses from sublimation.

Download Full-text

Spatial and temporal patterns of snow accumulation and aerial ablation across the McMurdo Dry Valleys, Antarctica

Hydrological Processes ◽

10.1002/hyp.9407 ◽

2012 ◽

pp. n/a-n/a ◽

Cited By ~ 4

Author(s):

Jeffery Eveland ◽

Michael N. Gooseff ◽

Derrick J. Lampkin ◽

J. E. Barrett ◽

Cristina Takacs-Vesbach

Keyword(s):

Temporal Patterns ◽

Snow Accumulation ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Spatial And Temporal Patterns

Download Full-text

Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica

Botany ◽

10.1139/b08-100 ◽

2008 ◽

Vol 86 (12) ◽

pp. 1378-1392 ◽

Cited By ~ 36

Author(s):

R. M.M. Esposito ◽

S. A. Spaulding ◽

D. M. McKnight ◽

B. Van de Vijver ◽

K. Kopalová ◽

...

Keyword(s):

Austral Summer ◽

Mcmurdo Dry Valleys ◽

Size Spectrum ◽

Dry Valleys ◽

Dominant Group ◽

Lower Range ◽

Glacial Ice ◽

Dry Valley ◽

James Ross Island ◽

Harsh Conditions

Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species ( Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6–10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent.

Download Full-text

The Mcmurdo Dry Valleys Long‐Term Ecological Rsearch Program: New understanding of the biogeochemistry of the Dry Valley Lakes: A review1

Polar Geography ◽

10.1080/10889370109377713 ◽

2001 ◽

Vol 25 (3) ◽

pp. 202-217 ◽

Cited By ~ 13

Author(s):

W. Berry Lyons ◽

Kathleen A. Welch ◽

John C. Priscu ◽

Johanna Labourn‐Parry ◽

Daryl Moorhead ◽

...

Keyword(s):

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Dry Valley

Download Full-text

The effects of joint ENSO–Antarctic Oscillation forcing on the McMurdo Dry Valleys, Antarctica

Antarctic Science ◽

10.1017/s0954102006000551 ◽

2006 ◽

Vol 18 (4) ◽

pp. 507-514 ◽

Cited By ~ 22

Author(s):

N.A.N. Bertler ◽

T.R. Naish ◽

H. Oerter ◽

S. Kipfstuhl ◽

P.J. Barrett ◽

...

Keyword(s):

Southern Oscillation ◽

Phase Relationship ◽

Snow Accumulation ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Antarctic Oscillation ◽

Summer Temperatures ◽

Temperature Records ◽

One Year ◽

Relationship Of

Stable oxygen analyses and snow accumulation rates from snow pits sampled in the McMurdo Dry Valleys have been used to reconstruct variations in summer temperature and moisture availability over the last four decades. The temperature data show a common interannual variability, with strong regional warmings occurring especially in 1984/85, 1995/96 and 1990/91 and profound coolings during 1977/78, 1983/84, 1988/89, 1993/94, and 1996/97. Annual snow accumulation shows a larger variance between sites, but the early 1970s, 1984, 1997, and to a lesser degree 1990/91 are characterized overall by wetter conditions, while the early and late 1980s show low snow accumulation values. Comparison of the reconstructed and measured summer temperatures with the Southern Oscillation Index (SOI) and the Antarctic Oscillation (AAO) yield statistically significant correlations, which improve when phase-relationships are considered. A distinct change in the phase relationship of the correlation is observed, with the SOI-AAO leading over the temperature records by one year before, and lagging by one year after 1988. These results suggest that over the last two decades summer temperatures are influenced by opposing El Niño Southern Oscillation and AAO forcings and support previous studies that identified a change in the Tropical-Antarctic teleconnection between the 1980s and 1990s.

Download Full-text

Extreme streams: flow intermittency as a control on diatom communities in meltwater streams in the McMurdo Dry Valleys, Antarctica1This article is derived from a special session entitled “A New Hydrology: Inflow Effects on Ecosystem Form and Functioning” that took place at the February 2011 ASLO Aquatic Sciences conference in San Juan, Puerto Rico.

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2012-022 ◽

2012 ◽

Vol 69 (8) ◽

pp. 1405-1419 ◽

Cited By ~ 20

Author(s):

Lee F. Stanish ◽

Tyler J. Kohler ◽

Rhea M.M. Esposito ◽

Breana L. Simmons ◽

Uffe N. Nielsen ◽

...

Keyword(s):

Community Composition ◽

Endemic Species ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Intermittent Streams ◽

Diatom Community ◽

Diatom Communities ◽

Dry Valley ◽

Flow Intermittency ◽

Diatom Community Composition

In the McMurdo Dry Valleys of Antarctica, stream biota is limited by the brief availability of liquid water. The benthic microbial mats harbor diatoms that have adapted to hydrologic stresses, including numerous endemic species. We found a strong relationship between diatom community composition and flow intermittency in a data set including seven streams that spanned a gradient in flow intermittency. In particular, two genera represented by numerous endemic species in Dry Valley habitats, Hantzschia and Luticola , had high abundances in moderately and highly intermittent streams, respectively. The Shannon Index of diversity was greatest in streams with intermediate flow intermittency, with lower diversity in more stable streams resulting from lower evenness, and lower diversity in highly intermittent streams resulting from lower richness. These results indicate that multiple metrics of biodiversity may be useful in assessing the response of diatom communities to changing hydrologic regime. We propose that flow intermittency acts as a species filter that increases habitat heterogeneity in Dry Valley streams and may allow endemic species to persist. Future Antarctic warming may alter diatom community composition and habitats that act as refugia for desiccation-tolerant taxa.

Download Full-text