The southernmost worm, Scottnema lindsayae (Nematoda): diversity, dispersal and ecological stability

Adams, Byron J.; Wall, Diana H.; Gözel, Uğur; Dillman, Adler R.; Chaston, John M.; Hogg, Ian D.

doi:10.1007/s00300-006-0241-3

Cited by 46 publications

(33 citation statements)

References 34 publications

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“…These observations point to localized, genetically disparate bacterial populations in the Dry Valleys, and suggest potential endemism in Dry Valley soil microbiota. These ideas challenge the notion that aeolian transport has a major role in inter-valley biota distribution (Adams et al, 2007). Although it is tempting to compare the level of spatial heterogeneity observed here with those of more temperate ecosystems, differences in sampling strategy and analysis methodology make such comparisons unreliable.…”

Section: Discussionmentioning

confidence: 67%

The Inter-Valley Soil Comparative Survey: the ecology of Dry Valley edaphic microbial communities

et al. 2011

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Recent applications of molecular genetics to edaphic microbial communities of the McMurdo Dry Valleys and elsewhere have rejected a long-held belief that Antarctic soils contain extremely limited microbial diversity. The Inter-Valley Soil Comparative Survey aims to elucidate the factors shaping these unique microbial communities and their biogeography by integrating molecular genetic approaches with biogeochemical analyses. Although the microbial communities of Dry Valley soils may be complex, there is little doubt that the ecosystem's food web is relatively simple, and evidence suggests that physicochemical conditions may have the dominant role in shaping microbial communities. To examine this hypothesis, bacterial communities from representative soil samples collected in four geographically disparate Dry Valleys were analyzed using molecular genetic tools, including pyrosequencing of 16S rRNA gene PCR amplicons. Results show that the four communities are structurally and phylogenetically distinct, and possess significantly different levels of diversity. Strikingly, only 2 of 214 phylotypes were found in all four valleys, challenging a widespread assumption that the microbiota of the Dry Valleys is composed of a few cosmopolitan species. Analysis of soil geochemical properties indicated that salt content, alongside altitude and Cu2+, was significantly correlated with differences in microbial communities. Our results indicate that the microbial ecology of Dry Valley soils is highly localized and that physicochemical factors potentially have major roles in shaping the microbiology of ice-free areas of Antarctica. These findings hint at links between Dry Valley glacial geomorphology and microbial ecology, and raise previously unrecognized issues related to environmental management of this unique ecosystem.

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Section: Discussionmentioning

confidence: 67%

The Inter-Valley Soil Comparative Survey: the ecology of Dry Valley edaphic microbial communities

et al. 2011

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“…The unusually inhospitable soil conditions outside the wetted area are highlighted by the very low occurrence of S. lindsayae. While this nematode is often found in the drier, saltier soils throughout the MDVs (Adams et al 2007), it appears that the conditions of the soils outside the wetted zone in the WHC watershed are so harsh that even this species is unable to sustain viable populations.…”

Section: Discussionmentioning

confidence: 99%

“…Dispersal via overland flow may be important for the soil fauna within the MDV due to the greater chance of being transported to suitable habitat that receive water flow regularly. Yet, wind dispersal allows animals to colonize hotspots of habitable soils throughout the landscape that are not connected by flowing water and may therefore be a main factor for colonization of otherwise unconnected habitable areas (Nkem et al 2006b, Adams et al 2007). …”

Section: Discussionmentioning

confidence: 99%

The ecology of pulse events: insights from an extreme climatic event in a polar desert ecosystem

et al. 2012

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Abstract. Climate change is occurring globally, with wide ranging impacts on organisms and ecosystems alike. While most studies focus on increases in mean temperatures and changes in precipitation, there is growing evidence that an increase in extreme events may be particularly important to altering ecosystem structure and function. During extreme events organisms encounter environmental conditions well beyond the range normally experienced. Such conditions may cause rapid changes in community composition and ecosystem states. We present the impact of an extreme pulse event (a flood) on soil communities in an Antarctic polar desert. Taylor Valley, McMurdo Dry Valleys, is dominated by large expanses of dry, saline soils. During the austral summer, melting of glaciers, snow patches and subsurface ice supplies water to ephemeral streams and wetlands. We show how the activation of a nonannual ephemeral stream, Wormherder Creek, and the associated wetland during an exceptional high-flow event alters soil properties and communities. The flow of water increased soil water availability and decreased salinity within the wetted zone compared with the surrounding dry soils. We propose that periodic leaching of salts from flooding reduces soil osmotic stress to levels that are more favorable for soil organisms, improving the habitat suitability, which has a strong positive effect on soil animal abundance and diversity. Moreover, we found that communities differentiated along a soil moisture gradient and that overland water flow created greater connectivity within the landscape, and is expected to promote soil faunal dispersal. Thus, floods can 'precondition' soils to support belowground communities by creating conditions below or above key environmental thresholds. We conclude that pulse events can have significant long-term impacts on soil habitat suitability, and knowledge of pulse events is essential for understanding the present distribution and functioning of communities in soil ecosystems.

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“…Aeolian redistribution by saltation provides a localized dispersal mechanism (i.e., within valley) that has been demonstrated to create spatially autocorrelated distribution patterns in the Dry Valleys for soil micro-and meiofauna (Nkem et al 2006, Adams et al 2007), including cyanobacteria (Wood et al 2008, Michaud et al 2012, Niederberger et al 2012, and drives local scale (i.e., within valley) heterogeneity in community composition. Aeolian redistribution of cyanobacterial cells (Wood et al 2008) combined v www.esajournals.org with the legacy of the historical influence of liquid water in the landscape (Moorhead et al 1999(Moorhead et al , 2003 appear to interact to create a heterogeneous patchwork of cyanobacterial assemblages over spatial gradients ,3 km.…”

Section: Local and Regional Influences Over Antarctic Microbial Metacmentioning

confidence: 99%

Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains

Sokol¹,

Herbold²,

Lee³

et al. 2013

Ecosphere

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Abstract. The metacommunity concept provides a useful framework to assess the influence of local and regional controls over diversity patterns. Culture-independent studies of soil microbial communities in the McMurdo Dry Valleys of East Antarctica (778 S) have shown that bacterial diversity is related to soil geochemical gradients, while studies targeting edaphic cyanobacteria have linked local diversity patterns to dispersal-based processes. In this study, we increased the spatial extent of observed soil microbial communities to cover the Beardmore Glacier region in the central Transantarctic Mountains (848 S). We used community profiling techniques to characterize diversity patterns for bacteria and the cyanobacterial subcomponent of the microbial community. Diversity partitioning was used to calculate beta diversity and estimate among-site dissimilarity in the metacommunity. We then used variation partitioning to assess the relationship between beta diversity and environmental and spatial gradients. We found that dominant groups in the soil bacterial metacommunity were influenced by gradients in pH and soil moisture at the Transantarctic scale (800 km). Conversely, beta diversity for the cyanobacterial component of the edaphic microbial metacommunity was decoupled from these environmental gradients, and was more related to spatial filters, suggesting that wind-driven dispersal dynamics created cyanobacterial biogeography at a local scale (,3 km).

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The southernmost worm, Scottnema lindsayae (Nematoda): diversity, dispersal and ecological stability

Cited by 46 publications

References 34 publications

The Inter-Valley Soil Comparative Survey: the ecology of Dry Valley edaphic microbial communities

The Inter-Valley Soil Comparative Survey: the ecology of Dry Valley edaphic microbial communities

The ecology of pulse events: insights from an extreme climatic event in a polar desert ecosystem

Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains

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