Community structure and physiological characterization of microbial mats in Byers Peninsula, Livingston Island (South Shetland Islands, Antarctica)

Fernández‐Valiente, Eduardo; Camacho, Antonio; Rochera, Carlos; Rico, Eugenio; Vincent, Warwick F.; Quesada, Antonio

doi:10.1111/j.1574-6941.2006.00221.x

Cited by 71 publications

(71 citation statements)

References 33 publications

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“…Two basic types of pigments are produced to protect algal tissues. Scytonemin is a colored pigment that occurs in the extracellular polysaccharide sheaths of cyanobacteria (Garcia-Pichel and Castenholz, 1991), and has been observed in microbial mats (Fernández-Valiente et al, 2007) and soil crust biofilms exposed to desiccation and high solar radiation (Belnap et al, 2005). Another group captures free radicals generated by UV penetration within the cell.…”

Section: Functional Changes and Adaptations Of Biofilms To Dry And Wementioning

confidence: 99%

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Sabater

Timoner

Borrego

et al. 2016

Front. Environ. Sci.

102

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Temporary streams are characterized by the alternation of dry and wet hydrological phases, creating both a harsh environment for the biota as well as a high diversity of opportunities for adaptation. These systems are mainly microbial-based during several of these hydrological phases, and those growing on all solid substrata (biofilms) accordingly change their physical structure and community composition. Biofilms experience large decreases in cell densities and biomass, both of bacteria and algae, during dryness. Algal and bacterial communities show remarkable decreases in their diversity, at least locally (at the habitat scale). Biofilms also respond with significant physiological plasticity to each of the hydrological changes. The decreasing humidity of the substrata through the drying process, and the changing quantity and quality of organic matter and nutrients available in the stream during that process, causes unequal responses on the biofilm bacteria and algae. Biofilm algae are affected faster than bacteria by the hydric stress, and as a result the ecosystem respiration resists longer than gross primary production to the increasing duration of flow intermittency. This response implies enhancing ecosystem heterotrophy, a pattern that can be exacerbated in temporary streams suffering of longer dry periods under global change.Keywords: biofilm, dry-rewetting cycle, temporary, intermittency, bacteria, algae, Mediterranean THE RELEVANCE OF TEMPORARY STREAMS IN THE WORLDFlow intermittency is part of the natural hydrology for streams and rivers, especially in arid and semi-arid landscapes. Temporary streams, or those that cease to flow at some points in space and time along their course, are a large fraction of many river networks, basically in tributaries of small order, but also in segments in the middle and lower parts of river networks. The number of temporary streams has been probably underestimated , as it appears from the application of novel on-site sensors, advances in remote sensing, and new modeling approaches. Flow intermittency has been estimated to account for 69% of first-order streams below 60 • , and up to 34% of larger order rivers (Raymond et al., 2013). Flow intermittency produces periodic or eventrelated loss of hydrologic connectivity between stream compartments, with consequences for all the processes ongoing in a waterway. Thus, flow intermittency triggers a chain of cascading effects eventually affecting water chemistry and biogeochemistry, as well as biodiversity, and ultimately community structure and ecosystem functioning.The direct implications of climate change and anomalous climatic events on flow regime are behind of the increasing temporality of many streams and rivers. Complex planetary scale processes, as well as local processes, may justify these situations. Anomalies such as the El Niño

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Section: Functional Changes and Adaptations Of Biofilms To Dry And Wementioning

confidence: 99%

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Sabater

Timoner

Borrego

et al. 2016

Front. Environ. Sci.

102

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“…Microbial mats exudate extracellular polymeric substances (EPS) and dissolved organic carbon (DOC) that may contribute to fuel bacterial production in lakes [23]. Furthermore, an extra supply of nitrogen might come from the activity of the nitrogen-fi xing cyanobacteria present in these mats [23].…”

Section: Trophic Links and Bio-geochemical Cyclesmentioning

confidence: 99%

Maritime Antarctic Lakes As Sentinels Of Climate Change

Camacho

Rochera

Villaescusa

et al. 2012

Lake Sustainability

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Remote lakes, such as lakes from the Maritime Antarctica, can be used as sentinels of climate change, because they are mostly free of direct anthropogenic pressures, and they experience climate change as a main stressor capable of modifying the ecosystem structure and function. In this paper, the content of a lecture that has been presented at the First Conference of Lake Sustainability, which has been centred in our studies on lakes from Byers Peninsula (Maritime Antarctica), are summarized. These included physical, chemical and biological studies of these lakes and other freshwater ecosystems, which highlighted the relevance of biotic interactions for these ecosystems and its sensibility to temperature variations and to biological invasions, which is of relevance given the acute regional warming occurring during the last decades in the area, concomitant with the enhancement of dispersion of alien species linked to the increased presence of humans.

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“…The harsh conditions prevent the survival of most macroorganisms but allow diverse microbial life to thrive and dominate (Vincent, 2000a;Vincent and Quesada, 2012). A common group of microbial communities found in the terrestrial and lacustrine environments of both polar regions are those forming "macro-biofilms, " which are highly organized structures which can have vertical differentiation of functional and physiological assemblages (Fernández-Valiente et al, 2007;Mohit et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Pole-to-Pole Connections: Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

et al. 2017

Self Cite

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The global biogeography of microorganisms remains poorly resolved, which limits the current understanding of microbial resilience toward environmental changes. Using high-throughput 16S rRNA gene amplicon sequencing, we characterized the microbial diversity of terrestrial and lacustrine biofilms from the Arctic, Antarctic and temperate regions. Our analyses suggest that bacterial community compositions at the poles are more similar to each other than they are to geographically closer temperate habitats, with 32% of all operational taxonomic units (OTUs) co-occurring in both polar regions. While specific microbial taxa were confined to distinct regions, representing potentially endemic populations, the percentage of cosmopolitan taxa was higher in Arctic (43%) than in Antarctic samples (36%). The overlap in polar microbial OTUs may be explained by natural or anthropogenically-mediated dispersal in combination with environmental filtering. Current and future changing environmental conditions may enhance microbial invasion, establishment of cosmopolitan genotypes and loss of endemic taxa.

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Community structure and physiological characterization of microbial mats in Byers Peninsula, Livingston Island (South Shetland Islands, Antarctica)

Cited by 71 publications

References 33 publications

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Maritime Antarctic Lakes As Sentinels Of Climate Change

Pole-to-Pole Connections: Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

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