Reactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment

McKnight, Diane M.; Tate, Cathy M.; Andrews, E. D.; Niyogi, Dev K.; Cozzetto, Karen; Welch, Kathleen A.; Lyons, W. Berry; Capone, Douglas G.

doi:10.1016/j.geomorph.2006.07.025

Cited by 77 publications

(94 citation statements)

References 34 publications

(40 reference statements)

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“…Because of strict regulations on performing manipulative experiments in the Dry Valleys, our observations were based on results from transplanting a single mummified seal carcass. However, few manipulative experiments of any sort have been performed in situ in the Dry Valleys 19,28 , which in part accounts for the unexpected character of our results.…”

Section: Discussionmentioning

confidence: 87%

“…Our findings show that indigenous microbial communities of Dry Valley soils can experience rapid and sustained structural alterations in response to contemporary variance in environmental conditions. Because the communities examined do not reside in areas where rapid response might be expected-such as streambeds 28 , lakeshores 19 and other hyporheic zones-this unexpected sensitivity to environmental disturbance is all the more striking, and may in fact characterize a substantial and previously unsuspected portion of Dry Valley microbiota. Physicochemical and biological activity measurements.…”

Section: Discussionmentioning

confidence: 98%

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Rapid microbial response to the presence of an ancient relic in the Antarctic Dry Valleys

et al. 2012

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 98%

Rapid microbial response to the presence of an ancient relic in the Antarctic Dry Valleys

et al. 2012

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“…In a recent review, Holzinger and Karsten (2013) found that some of these physiological strategies in green algae already adapted to desiccation favour a quick recovery when rewet, whereas aquatic species were more sensitive to drying. It has been shown that cyanobacterial mats in Antarctic environments recover photosynthetic activity, similar to rates before desiccation, in few minutes (Vicent and Howard-Williams 1986;Hawes et al 1992;McKnight et al 2007). Romaní and Sabater (1997) also observed the high resilience of stromatolite-like structures to quickly return to the photosynthetic activity they had before complete desiccation.…”

Section: Introductionmentioning

confidence: 99%

Photosynthetic pigment changes and adaptations in biofilms in response to flow intermittency

et al. 2014

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Among the environmental factors affecting benthic algae and cyanobacteria in streams, the one often producing the largest effects is flow intermittency. This study aimed to characterize the responses of algal assemblages to flow intermittency in a Mediterranean intermittent stream during the drying, non-flow (112 days), and rewetting phases. Algae growing in the epilithic, epipsammic and hyporheic streambed compartments were analyzed for pigment composition, and for the existence of structural changes in cells. Chlorophyll-a concentrations decreased between 60 to 90 % during the non-flow phase, indicating low resistance of algal assemblages to desiccation. In contrast, fast recoveries of Chlorophyll-a when flow resumed indicated high resilience. Pigment composition revealed that the epilithic algal assemblage was considerably different than the epipsammic and hyporheic ones. These differences were mainly attributed to the physical conditions prevailing on each streambed compartment that allowed the growth of different algal assemblages. During the non-flow phase, the synthesis of protective carotenoids (i.e. echinenone and scytonemin) and the occurrence of cell resistance structures (i.e. enlarged membrane thickness and resistant spores) enhanced resistance of the epilithic biofilm. The resistance observed in the epilithic biofilm might also be related to the tightly adhered growth-form of algae on this substratum. Main results suggest that algal assemblages in the epilithic compartment, which were the most exposed to desiccation, were structurally and functionally better adapted to flow interruption than those colonizing other streambed compartments, and that this compartment plays a crucial role in maintaining ecosystem functions under varying flow periods.

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“…Increased movement of water should not only increase the amount of habitat for those species normally occurring in moist soils, but decrease the abundance of organisms better adapted to the prevailing arid, saline soils such as the present dominant invertebrate: the nematode, S. lindsayae . Water dispersal of organisms will be enhanced transporting organisms among newly-connected landscape components, and thereby influencing biogeochemical cycling McKnight et al 2007;Barrett, Fig. 5 Soil conductivity in and around a re-activated stream fed by subsurface ice melt along the entire stretch of the stream (from just upslope of the stream emergence to the lake shore).…”

Section: The Future Of MDV Soil Biology and Biogeochemistrymentioning

confidence: 99%

Implications of meltwater pulse events for soil biology and biogeochemical cycling in a polar desert

et al. 2011

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The McMurdo Dry Valleys are one of the most arid environments on Earth. Over the soil landscape for the majority of the year, biological and ecosystem processes in the dry valleys are constrained by the low temperatures and limited availability of water. The prevalence of these physical limitations in controlling biological and ecosystem processes makes the dry valleys a climate-sensitive system, poised to experience substantial changes following projected future warming. Short-duration increases in summer temperatures are associated with pulses of water from melting ice reserves, including glaciers, snow and permafrost. Such pulses alter soil geochemistry by mobilizing and redistributing soil salts (via enhanced weathering, solubility and mobility), which can alter habitat suitability for soil organisms. Resulting changes in soil community composition or distribution may alter the biogeochemical processes in which they take part. Here, we review the potential impacts of meltwater pulses and present new field data documenting instances of meltwater pulse events that result from different water sources and hydrological patterns, and discuss their potential influence on soil biology and biogeochemistry. We use these examples to discuss the potential impacts of future climate change on the McMurdo Dry Valley soil ecosystem

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Reactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment

Cited by 77 publications

References 34 publications

Rapid microbial response to the presence of an ancient relic in the Antarctic Dry Valleys

Rapid microbial response to the presence of an ancient relic in the Antarctic Dry Valleys

Photosynthetic pigment changes and adaptations in biofilms in response to flow intermittency

Implications of meltwater pulse events for soil biology and biogeochemical cycling in a polar desert

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