Distribution, species composition and morphology of algal mats in Antarctic dry valley lakes

Wharton, Robert A.; Parker, Barry; Simmons, George M.

doi:10.2216/i0031-8884-22-4-355.1

Cited by 171 publications

(138 citation statements)

References 15 publications

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“…There is a sharp chlorophyll maximum in the planktonic community at ~8 m, just above the depth at which O 2 concentration and planktonic net photosynthesis fall to zero (e.g., Vincent, 1981;McKnight et al, 2000;Burnett et al, 2006;Vick-Majors et al, 2014). There are extensive benthic mat communities extending from the moat around the margin of the lake to ~11 m depth that are dominated by cyanobacteria, diatoms, and heterotrophic bacteria (e.g., Wharton et al, 1983;Taton et al, 2003).…”

Section: Lake Fryxellmentioning

confidence: 99%

Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases

Sumner

Hawes

Mackey

et al. 2015

Geology

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The evolution of oxygenic photosynthesis was the most important geochemical event in Earth history, causing the Great Oxidation Event (GOE) ~2.4 b.y. ago. However, evidence is mixed as to whether O 2 production occurred locally as much as 2.8 b.y. ago, creating O 2 oases, or initiated just prior to the GOE. The biogeochemical dynamics of possible O 2 oases have been poorly constrained due to the absence of modern analogs. However, cyanobacteria in microbial mats in a perennially anoxic region of Lake Fryxell, Antarctica, create a 1-2 mm O 2 -containing layer in the upper mat during summer, providing the first known modern analog for formation of benthic O 2 oases. In Lake Fryxell, benthic cyanobacteria are present below the oxycline in the lake. Mat photosynthesis rates were slow due to low photon flux rate (1-2 µmol m -2 s -1) under thick ice cover, but photosynthetic O 2 production was sufficient to sustain up to 50 µmol O 2 L -1

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Section: Lake Fryxellmentioning

confidence: 99%

Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases

Sumner

Hawes

Mackey

et al. 2015

Geology

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“…Early studies suggested that aquatic ecosystems in Antarctica contained low levels of cyanobacterial diversity. For example, only two cyanobacterial taxa, Phormidium frigidum and Lyngbya martensiana, were described in Lake Fryxell on the basis of microscopic observations (Wharton et al 1983). However, 20 years later, the use of both 16S rRNA genes and internal transcribed spacer (ITS) regions show an entirely different picture (Taton et al 2003a).…”

Section: Aquatic Habitatsmentioning

confidence: 99%

Ecology and biogeochemistry of cyanobacteria in soils, permafrost, aquatic and cryptic polar habitats

et al. 2015

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Polar Regions (continental Antarctica and the Arctic) are characterized by a range of extreme environmental conditions, which impose severe pressures on biological life. Polar cold-active cyanobacteria are uniquely adapted to withstand the environmental conditions of the high latitudes. These adaptations include high ultra-violet radiation and desiccation tolerance, and mechanisms to protect cells from freeze-thaw damage. As the most widely distributed photoautotrophs in these regions, cyanobacteria are likely the dominant contributors of critically essential ecosystem services, particularly carbon and nitrogen turnover in terrestrial polar habitats. These habitats include soils, permafrost, cryptic niches (including biological soil crusts, hypoliths and endoliths), ice and snow, and a range of aquatic habitats. Here we review current literature on the ecology, and the functional role played by cyanobacteria in various Arctic and Antarctic environments. We focus on the ecological importance of cyanobacterial communities in Polar Regions and assess what is known regarding the toxins they produce. We also review the responses and adaptations of cyanobacteria to extreme environments.

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“…Although it is unclear what processes determine the morphology of microbial mats, hypotheses include: microbial community composition (Gerdes et al 2000;Golubic et al 2000;Dupraz and Visscher 2005;Noffke 2010;Shepard and Sumner 2010), metazoan and protistan grazing (Garrett 1970;Bernhard et al 2013), hydrodynamics and sedimentation (Gebelein 1969;Martin et al 1993;Andres and Reid 2006;Mariotti et al 2014), and other environmental factors (Wharton et al 1983;Gerdes et al 2000;Petroff et al 2010). In modern environments, microbial mats in tidal flats, sabkhas, and shallow subtidal zones are commonly considered analogs and possible precursors to stromatolites (e.g., Browne et al 2000;Dupraz et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Gene Sequencing-Based Analysis of Microbial-Mat Morphotypes, Caicos Platform, British West Indies

Trembath‐Reichert¹,

Ward²,

Slotznick³

et al. 2016

Journal of Sedimentary Research

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Active carbonate platforms provide modern analogs to study microbial-mat development and taphonomy in the sedimentary record. Microbial-mat descriptions and classifications for tropical tidal-flat environments have focused predominantly on morphological observations. This is exemplified by flat and biscuit-shaped mats, where the mat morphotypes are postulated to reflect different Cyanobacteria communities as the main mat-building taxa. To compare the total microbial communities of these two mat types and test this Cyanobacteria hypothesis, we applied optical microscopy and gene sequencing methods using samples from a tidal algal marsh on Little Ambergris Cay, Turks and Caicos, B.W.I. With gene sequencing we find that total diversity and community composition differs significantly between morphotypes; the biscuit mat is more diverse than the flat mat. Microscopy results support that Cyanobacteria populations colonizing the surface layer of these two mat types are responsible for much of the mat's structural elements; however, genetic data find the Cyanobacteria population is indistinguishable between the two mat types. The recovered Cyanobacteria populations fall predominantly into three taxa: Scytonema, Halomicronema, and Crinalium. We propose that the morphology of these two mat types is not controlled by the Cyanobacteria, but instead reflects a time-integrated microbial response to environmental factors, where the microbial community becomes more diverse with time since environmental disturbance.

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Distribution, species composition and morphology of algal mats in Antarctic dry valley lakes

Cited by 171 publications

References 15 publications

Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases

Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases

Ecology and biogeochemistry of cyanobacteria in soils, permafrost, aquatic and cryptic polar habitats

Gene Sequencing-Based Analysis of Microbial-Mat Morphotypes, Caicos Platform, British West Indies

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