02591nas a2200229   4500008004100000245013200041210006900173260001200242300000600254490000600260520183600266100002102102700002402123700001802147700001602165700002202181700002402203700003302227700002402260700002202284856005502306       2023                        eng d00aImpact of meltwater flow intensity on the spatiotemporal heterogeneity of microbial mats in the McMurdo Dry Valleys, Antarctica0 aImpact of meltwater flow intensity on the spatiotemporal heterog  c01/2023  a30 v33 a<p>The meltwater streams of the McMurdo Dry Valleys are hot spots of biological diversity in the climate-sensitive polar desert landscape. Microbial mats, largely comprised of cyanobacteria, dominate the streams which flow for a brief window of time (~10 weeks) over the austral summer. These communities, critical to nutrient and carbon cycling, display previously uncharacterized patterns of rapid destabilization and recovery upon exposure to variable and physiologically detrimental conditions. Here, we characterize changes in biodiversity, transcriptional responses and activity of microbial mats in response to hydrological disturbance over spatiotemporal gradients. While diverse metabolic strategies persist between marginal mats and main channel mats, data collected from 4 time points during the austral summer revealed a homogenization of the mat communities during the mid-season peak meltwater flow, directly influencing the biogeochemical roles of this stream ecosystem. Gene expression pattern analyses identified strong functional sensitivities of nitrogen-fixing marginal mats to changes in hydrological activities. Stress response markers detailed the environmental challenges of each microhabitat and the molecular mechanisms underpinning survival in a polar desert ecosystem at the forefront of climate change. At mid and end points in the flow cycle, mobile genetic elements were upregulated across all mat types indicating high degrees of genome evolvability and transcriptional synchronies. Additionally, we identified novel antifreeze activity in the stream microbial mats indicating the presence of ice-binding proteins (IBPs). Cumulatively, these data provide a new view of active intra-stream diversity, biotic interactions and alterations in ecosystem function over a high-flow hydrological regime.</p>1 aZoumplis, Angela1 aKolody, Bethany, C.1 aKaul, Drishti1 aZheng, Hong1 aVenepally, Pratap1 aMcKnight, Diane, M.1 aTakacs-Vesbach, Cristina, D.1 aDeVries, Arthur, L.1 aAllen, Andrew, E.  uhttps://www.nature.com/articles/s43705-022-00202-802771nas a2200325   4500008004100000022001400041245013500055210006900190260001200259300001000271490000700281520179400288653001302082653001302095653001002108653001302118653002002131653001702151653001702168653003102185100002602216700001902242700002002261700002102281700001802302700002202320700002102342700002402363856005802387       2022                        eng d  a0022-364600aBlowin’ in the wind: Dispersal, structure, and metacommunity dynamics of aeolian diatoms in the McMurdo Sound region, Antarctica0 aBlowin in the wind Dispersal structure and metacommunity dynamic  c02/2022  a36-540 v583 a<p>Diatom metacommunities are structured by environmental, historical, and spatial factors that are often attributed to organism dispersal. In the McMurdo Sound region (MSR) of Antarctica, wind connects aquatic habitats through delivery of inorganic and organic matter. We evaluated the dispersal of diatoms in aeolian material and its relation to the regional diatom metacommunity using light microscopy and 18S rRNA high-throughput sequencing. The concentration of diatoms ranged from 0 to 8.76 * 10<sup>6</sup> valves &middot; g<sup>-1</sup> dry aeolian material. Up to 15% of whole cells contained visible protoplasm, indicating that up to 3.43 * 10<sup>4</sup> potentially viable individuals could be dispersed in a year to a single 2 cm<sup>2</sup>&nbsp;site. Diatom DNA and RNA was detected at each site, reinforcing the likelihood that we observed dispersal of viable diatoms. Of the 50 known morphospecies in the MSR, 72% were identified from aeolian material using microscopy. Aeolian community composition varied primarily by site. Meanwhile, each aeolian community was comprised of morphospecies found in aquatic communities from the same lake basin. These results suggest that aeolian diatom dispersal in the MSR is spatially structured, is predominantly local, and connects local aquatic habitats via a shared species pool. Nonetheless, aeolian community structure was distinct from that of aquatic communities, indicating that intrahabitat dispersal and environmental filtering also underlie diatom metacommunity dynamics. The present study confirms that a large number of diatoms are passively dispersed by wind across a landscape characterized by aeolian processes, integrating the regional flora and contributing to metacommunity structure and landscape connectivity.</p>10a18S rRNA10aairborne10aalgae10aassembly10aBacillariophyta10abiogeography10aconnectivity10ahigh-throughput sequencing1 aSchulte, Nicholas, O.1 aKhan, Alia, L.1 aSmith, Emma, W.1 aZoumplis, Angela1 aKaul, Drishti1 aAllen, Andrew, E.1 aAdams, Byron, J.1 aMcKnight, Diane, M.  uhttps://onlinelibrary.wiley.com/doi/10.1111/jpy.1322301971nas a2200181   4500008004100000245008500041210006900126260005200195520137400247100002101621700002101642700001801663700002101681700001301702700002001715700002001735856003401755       2020                        eng d00aFollowing the Astrobiology Roadmap: Origins, Habitability and Future Exploration0 aFollowing the Astrobiology Roadmap Origins Habitability and Futu  aNorfolk, United KingdombCaister Academic Press3 a<p>Astrobiology asks three fundamental questions as outlined by the NASA Astrobiology Roadmap: 1. How did Life begin and evolve?; Is there Life elsewhere in the Universe?; and, What is the future of Life on Earth? As we gain perspective on how Life on Earth arose and adapted to its many niches, we too gain insight into how a planet achieves habitability. Here on Earth, microbial Life has evolved to exist in a wide range of habitats from aquatic systems to deserts, the human body, and the International Space Station (ISS). Landers, rovers, and orbiter missions support the search for signatures of Life beyond Earth, by generating data on surface and subsurface conditions of other worlds. These have provided evidence for water activity, supporting the potential for extinct or extant Life. To investigate the putative ecologies of these systems, we study extreme environments on Earth. Several locations on our planet provide analog settings to those we have detected or expect to find on neighboring and distant worlds. Whereas, the field of space biology uses the ISS and low gravity analogs to gain insight on how transplanted Earth-evolved organisms will respond to extraterrestrial environments. Modern genomics allows us to chronicle the genetic makeup of such organisms and provides an understanding of how Life adapts to various extreme environments.</p>1 aO'Rourke, Aubrie1 aZoumplis, Angela1 aWilburn, Paul1 aLee, Michael, D.1 aLee, Zhi1 aVecina, Marissa1 aMercader, Kysha  uhttps://www.caister.com/astro