01860nas a2200205 4500008004100000022001400041245015300055210006900208260001200277520112000289100002201409700002001431700002001451700002501471700001701496700002401513700002501537700002401562856006801586 2021 eng d a2378-224200aFrom the Heroic Age to today: What diatoms from Shackleton's Nimrod expedition can tell us about the ecological trajectory of Antarctic ponds0 aFrom the Heroic Age to today What diatoms from Shackletons iNimr c07/20213 a

Biological invasion and environmental change pose major threats to ecosystems. While long-term ecological change is commonly evaluated through sediment cores in lakes, it is generally not feasible for smaller ponds, and spatial resolution is limited. Here, we analyze pond diatom communities collected during Shackleton's Nimrod expedition at Cape Royds, Antarctica, to compare with the same waterbodies a century later. We find historical samples to be almost identical to modern counterparts, and provide no evidence of exotic introductions despite increasing human activity. However, a shift occurred in the pond nearest Shackleton's hut, Pony Lake, which was dominated by Luticola muticopsis a century ago, and was replaced by Craspedostauros laevissimus. Both are endemic species previously and currently present at Cape Royds, and we hypothesize that a shift in conductivity accompanying changing precipitation patterns may be responsible. Collectively, these results provide important data for assessing human and climate impacts among Antarctic lacustrine habitats.

1 aKohler, Tyler, J.1 aHowkins, Adrian1 aSokol, Eric, R.1 aKopalová, Kateřina1 aCox, Aneliya1 aDarling, Joshua, P.1 aGooseff, Michael, N.1 aMcKnight, Diane, M. uhttps://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lol2.1020001971nas 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

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.

1 aO'Rourke, Aubrie1 aZoumplis, Angela1 aWilburn, Paul1 aLee, Michael, D.1 aLee, Zhi1 aVecina, Marissa1 aMercader, Kysha uhttps://www.caister.com/astro02262nas a2200181 4500008004100000022001400041245010300055210006900158260001200227300001600239490000800255520165500263100002201918700001701940700001501957700002401972856008401996 2018 eng d a2169-895300aFe and Nutrients in Coastal Antarctic Streams: Implications for Primary Production in the Ross Sea0 aFe and Nutrients in Coastal Antarctic Streams Implications for P c12/2018 a3507 - 35220 v1233 a

The Southern Ocean (SO) has been an area of biogeochemical interest due to the presence of macronutrients (N, P, and Si) but lack of the expected primary production response, which is thought to be primarily due to Fe limitation. Because primary production is associated with increased drawdown of atmospheric CO2, it is important to quantify the fluxes of Fe and other nutrients into the SO. Here we present data from subaerial streams that flow into the Ross Sea, a sector of the coastal SO. Water samples were collected in the McMurdo Dry Valleys, Antarctica, and analyzed for macronutrients and Fe to determine the potential impact of terrestrial water input on the biogeochemistry of coastal oceanic waters. The physiochemical forms of Fe were investigated through analysis of three operationally defined forms: acid-dissolvable Fe (no filtration), filterable Fe (<0.4 μm), and dissolved Fe (<0.2 μm). The combined average flux from two McMurdo Dry Valley streams was approximately 240 moles of filterable Fe per year. The dissolved fraction of Fe made up 18%–27% of the filterable Fe. The stream data yield an average filterable stoichiometry of N3P1Si100Fe0.8, which is substantially different from the planktonic composition and suggests that these streams are a potential source of Fe and P, relative to N and Si, to coastal phytoplankton communities. While the Fe flux from these streams is orders of magnitude less than estimated eolian and iceberg sources, terrestrial streams are expected to become a more significant source of Fe to the Ross Sea in the future.

1 aOlund, Sydney, A.1 aLyons, Berry1 aWelch, Sue1 aWelch, Kathleen, A. uhttps://agupubs.pericles-prod.literatumonline.com/doi/full/10.1029/2017JG00435202715nas a2200133 4500008004100000245011000041210006900151260002600220490000900246520222000255100002202475700001702497856006702514 2017 eng d00aFe and Nutrients in Coastal Antarctic Streams: Implications for Marine Primary Production in the Ross Sea0 aFe and Nutrients in Coastal Antarctic Streams Implications for M bOhio State University0 vM.S.3 a

The Southern Ocean (SO) has been an area of much biogeochemical interest due to the role of Fe limitation for primary production. Primary production is associated with increased carbon sequestration, making it important to characterize and quantify the fluxes of Fe and other nutrients to the ocean. Water samples were collected in the McMurdo Dry Valleys, Antarctica (MDV) from four subaerial streams flowing into the Ross Sea. They were analyzed for macronutrients (N, P, Si) and Fe to determine the potential impact of terrestrial water input on the biogeochemistry of coastal oceanic waters. Our stream data yield an average filterable composition of N3P1 Si100Fe0.8, which is substantially different from the planktonic composition as demonstrated by empirical measurements, and suggests that these streams are a potential source of Fe and P, relative to N and Si, to coastal phytoplankton communities.

The behavior and potential colloidal/nanoparticulate speciation of the Fe in these streams was investigated through analysis of three physiochemical forms of Fe - environmentally active Fe (acid-soluble/no filtration), filterable Fe (filtered through 0.4 μm), and dissolved Fe (filtered through 0.2 μm). It has been suggested that the dissolved fraction is mainly nanoparticulate and represents a more bioavailable form of Fe, as compared with colloids and particles. Overall, the combined average annual flux from two MDV streams is approximately 240 moles fFe yr-1, which is consistent with previously predicted values. The dissolved fraction of Fe (<0.2 μm) was between 18% and 27% percent of the fFe, meaning the fFe pool is mostly colloidal. While the Fe flux from these streams is several orders of magnitude less than aeolian and iceberg sources, terrestrial streams are expected to become a more significant source of Fe to the Ross Sea. As the Antarctic climate warms, ice-free regions similar to the MDV should increase in extent and glacier melt. This study questions how, and in what quantities, Fe is solubilized and transported from the landscape into the SO to better inform predictions of Fe fluxes following continued warming.
1 aOlund, Sydney, A.1 aLyons, Berry uhttp://rave.ohiolink.edu/etdc/view?acc_num=osu149269789434354602308nas a2200217 4500008004100000022001400041245010100055210006900156260001200225300001400237490000700251520161900258100002501877700001601902700002001918700002201938700002401960700001801984700002402002856006402026 2017 eng d a0722-406000aFreshwater diatom biogeography and the genus Luticola: an extreme case of endemism in Antarctica0 aFreshwater diatom biogeography and the genus Luticola an extreme c03/2017 a1185-11960 v403 a

Historical views have characterized Antarctica as a frozen desert with low diversity, although recent studies suggest that this may not be true for microscopic organisms. For microbes, assessing endemism in the Antarctic region has been particularly important, especially against a backdrop of debate regarding their presumed cosmopolitan nature. To contribute to this conversation, we highlight the observed endemism of the freshwater diatom genus Luti- cola in Antarctica by synthesizing the results of a modern high-resolution taxonomy from the Continental, Maritime, and sub-Antarctic regions. We report that Luticola has one of the highest endemic rates of any diatom genus in Antarctica, in terms of total number of species (taxon endemism) and percentage of the entire genus (phylogenetic endemism). Of the over 200 species of Luticola globally, nearly 20% (43) occur in the Antarctic, with 42 of these being endemic. Within regions, Maritime Antarctica has the largest number of Luticola species and endemics (28 and 23, respectively), followed by Continental Antarctica (14, 9) and sub-Antarctic islands (8, 6). Thus, 38 of the 42 endemics are found in a single region only. While the timing of Luticola diversi cation has not been established, fossil evidence suggests recent invasions and/or diversi cation over a relatively short geologic timescale. Understanding the origin and evolution of endemic diatom species in Antarctica will help us better understand microbial biogeography, as well as assess and interpret impacts of large-scale environmental change taking place at southern latitudes.

1 aKociolek, J. Patrick1 aKopalova, K1 aHamsher, S., E.1 aKohler, Tyler, J.1 aVan de Vijver, Bart1 aConvey, Peter1 aMcKnight, Diane, M. uhttps://link.springer.com/article/10.1007/s00300-017-2090-702886nas a2200133 4500008004100000245007600041210006900117260002900186300000800215490001000223520238000233100002502613856011402638 2016 eng d00aFactors influencing the abundance of microorganisms in icy environments0 aFactors influencing the abundance of microorganisms in icy envir bMontana State University a2360 vPh.D.3 a

Microbial life can easily live without us; we, however, cannot survive without the global catalysis and environmental transformations it provides (Falkowski et al., 2008). Despite of the key role of microbes on Earth, microbial community characteristics are not explicitly part of climate models because our understanding of their responses to long-term environmental and climatic processes is limited. In this study, I developed a Flow Cytometric protocol to access a long-term record of non-photosynthetic prokaryotic cell concentration archived in the West Antarctic Ice-Sheet (WAIS; chapter 2). The WD ice core was retrieved between 2009 and 2011 to a depth of 3,405 m, extending back to 68,000 before 1950. Once a 17,400 year-record of prokaryotic cell concentration was acquired, I investigated its temporal variability and patterns, determined the potential sources of prokaryotic cells between the Last Glacial Maximum and the early Holocene, and assessed the environmental factors that might have the largest influence on the prokaryotic response (chapter 3). The observed patterns in the prokaryotic record are linked to large-scale controls of the Southern Ocean and West Antarctica Ice-Sheet. The main research findings presented here about the first prokaryotic record are: (i) airborne prokaryotic cell concentration does respond to long-term climatic and environmental processes, (ii) the processes of deglaciation, sea level rise and sea-ice fluctuation were key; the abundance of prokaryotic cells covariate with ssNa and black carbon, and (iii) the prokaryotic cell record variate on millennial time scale with cycles of 1,490-years. In addition, I studied congelation ice (i.e., ice forms as liquid water freezes) from ice-covered lakes to understand prokaryotic cell segregation between liquid and solid phases during the physical freezing process. Five mesocosm experiments were designed to understand prokaryotic responses to the progressive freezing in concert with field observations from ice-covered lakes from Barrow, Alaska. As a result of this last study (chapter 4), I concluded that prokaryotic cells are preferentially incorporated in the ice with segregation coefficients (Keff) between 0.8–4.4, which are higher than for major ions. Prokaryotic cells avoid rejection more effectively from the ice matrix.

1 aSantibáñez, Pamela uhttps://search.proquest.com/openview/eb36d8ca7f2f1308b69e87a6c37f0a72/1?pq-origsite=gscholar&cbl=18750&diss=y02358nas a2200229 4500008004100000022001400041245011300055210006900168260001200237490000600249520163400255100002801889700001901917700001901936700002401955700001601979700001701995700001902012700002002031700002102051856005602072 2015 eng d a2150-892500aFostering ecological data sharing: collaborations in the International Long Term Ecological Research Network0 aFostering ecological data sharing collaborations in the Internat c10/20150 v63 a

The International Long Term Ecological Research (ILTER) Network was established in 1993 and is now composed of thirty-eight national networks representing a diversity of ecosystems around the globe. Data generated by the ILTER Network are valuable for scientists addressing broad spatial and temporal scale research questions, but only if these data can be easily discovered, accessed, and understood. Challenges to publishing ILTER data have included unequal distribution among networks of information management expertise, user-friendly tools, and resources. Language and translation have also been issues. Despite these significant obstacles, ILTER information managers have formed grassroots partnerships and collaborated to provide information management training, adopt a common metadata standard, develop information management tools useful throughout the network, and organize scientist/information manager workshops that encourage scientists to share and integrate data. Throughout this article, we share lessons learned from the successes of these grassroots international partnerships to inform others who wish to collaborate internationally on projects that depend on data sharing entailing similar management challenges.
 

1 aVanderbilt, Kristin, L.1 aLin, Chau-Chin1 aLu, Sheng-Shan1 aKassim, Abd, Rahman1 aHe, Honglin1 aGuo, Xuebing1 aSan Gil, Inigo1 aBlankman, David1 aPorter, John, H. uhttp://www.esajournals.org/doi/10.1890/ES14-00281.101873nas a2200241 4500008004100000022001400041245005200055210005100107260001200158300001400170490000700184520122300191100001401414700001501428700002001443700002101463700001501484700001401499700001601513700002001529700001501549856006701564 2014 eng d a1084-545300aForum: Climate Change and Environmental History0 aForum Climate Change and Environmental History c04/2014 a281 - 3640 v193 a

This Forum explores global climate change, one of this century's most prominent environmental issues. Authors answer two critical questions: (1) How does the study of climate history enrich the field of environmental history more broadly? (2) How can environmental historians contribute to present-day understandings of and responses to global climate change? This introductory essay (and the Forum more generally) contribute to both environmental history research and climate change discussions by grappling with several key issues including the agency of nonhuman nature and environmental determinism, environmental governance, climate as a cultural construction, the history of environmental ideas and discourse, environmental narratives, the commodification of nature, and the politicization of the natural and life sciences. This essay also shows how the study of climate history provides methodological and practical tools for environmental historians. It analyzes the role of interdisciplinary sources and archives, scale, the place of science in environmental history scholarship, and the relevance of environmental histories for present-day policymaking and public discussions about climate change.

1 aCarey, M.1 aGarone, P.1 aHowkins, Adrian1 aEndfield, G., H.1 aCulver, L.1 aWhite, S.1 aJohnson, S.1 aFleming, J., R.1 aGarone, P. uhttp://envhis.oxfordjournals.org/cgi/doi/10.1093/envhis/emu00400764nas a2200205 4500008004100000245015000041210006900191260001200260300001100272490000600283100002400289700001800313700002200331700002500353700002500378700002100403700002200424700003300446856007900479 2013 eng d00aFactors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale0 aFactors Controlling Soil Microbial Biomass and Bacterial Diversi c06/2013 ae661030 v81 aVan Horn, David, J.1 aVan Horn, Lee1 aBarrett, John, E.1 aGooseff, Michael, N.1 aAltrichter, Adam, E.1 aGeyer, Kevin, M.1 aZeglin, Lydia, H.1 aTakacs-Vesbach, Cristina, D. uhttp://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.006610300566nas a2200133 4500008004100000245013000041210006900171260001200240300001400252490000700266100002200273700002000295856011700315 2013 eng d00aThe future of soil invertebrate communities in polar regions: different climate change responses in the Arctic and Antarctic?0 afuture of soil invertebrate communities in polar regions differe c03/2013 a409 - 4190 v161 aNielsen, Uffe, N.1 aWall, Diana, H. uhttp://onlinelibrary.wiley.com/doi/10.1111/ele.12058/abstract;jsessionid=2591020317030CE8FCDC37FE39B4F0B2.f01t0400484nam a2200121 4500008004100000020001800041245006800059210006700127260003300194100001800227700002100245856009600266 2011 eng d a0-309-21087-900aFrontiers in Understanding Climate Change and Polar Ecosystems0 aFrontiers in Understanding Climate Change and Polar Ecosystems bThe National Academies Press1 aGrebmeier, J.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/frontiers-understanding-climate-change-and-polar-ecosystems00641nas a2200181 4500008004100000020001800041245006900059210006900128260003100197300001200228490000600240100003300246700002200279700002500301700002200326700002100348856009000369 2010 eng d a978052188919300aFactors promoting microbial diversity in the McMurdo Dry Valleys0 aFactors promoting microbial diversity in the McMurdo Dry Valleys bCambridge University Press a221-2570 v51 aTakacs-Vesbach, Cristina, D.1 aZeglin, Lydia, H.1 aGooseff, Michael, N.1 aBarrett, John, E.1 aPriscu, John, C. uhttp://ebooks.cambridge.org/chapter.jsf?bid=CBO9780511712258&cid=CBO9780511712258A01500439nas a2200133 4500008004100000245005000041210005000091300001200141490000700153100002300160700002200183700002100205856007900226 2006 eng d00aFuel movement between grain boundaries in ice0 aFuel movement between grain boundaries in ice a158-1650 v451 aJepsen, Steven, M.1 aAdams, Edward, E.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/fuel-movement-between-grain-boundaries-ice00567nas a2200169 4500008004100000245009200041210006900133260001200202300001000214490000800224100002100232700002700253700002700280700002100307700002200328856004700350 2003 eng d00aFormation and character of an ancient 19 m ice cover and underlying trapped brine in an0 aFormation and character of an ancient 19 m ice cover and underly c01/2003 a26-310 v1001 aDoran, Peter, T.1 aFritsen, Christian, H.1 aMcKay, Christopher, P.1 aPriscu, John, C.1 aAdams, Edward, E. uhttp://www.pnas.org/content/100/1/26.short00733nas a2200193 4500008004100000245014900041210006900190300001200259490000600271100001500277700002100292700001900313700001400332700001400346700001900360700001500379700002100394856012400415 2003 eng d00aFourier-transform raman spectroscopic studies of organic and inorganic chemical components in stromatolitic cores from Antarctic lake sediments0 aFouriertransform raman spectroscopic studies of organic and inor a325-3310 v11 aEdwards, H1 aWynn-Williams, D1 aEllis-Evans, J1 aNewton, E1 aLittle, S1 ade Oliveira, L1 aHodgson, D1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/fourier-transform-raman-spectroscopic-studies-organic-and-inorganic-chemical-components00499nas a2200121 4500008004100000245008700041210006900128490000600197100002000203700002000223700002300243856011100266 2002 eng d00aField and microcosm studies of decomposition and soil biota in a cold dessert soil0 aField and microcosm studies of decomposition and soil biota in a0 v51 aTreonis, Amy, M1 aWall, Diana, H.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/field-and-microcosm-studies-decomposition-and-soil-biota-cold-dessert-soil00460nas a2200109 4500008004100000245009300041210006900134300001200203490000700215100001700222856011100239 2002 eng d00aFlux of eolian sediment in the Mcmurdo Dry Valleys, Antarctica: a preliminary assessment0 aFlux of eolian sediment in the Mcmurdo Dry Valleys Antarctica a  a318-3230 v341 aLancaster, N uhttps://mcm.lternet.edu/content/flux-eolian-sediment-mcmurdo-dry-valleys-antarctica-preliminary-assessment00674nas a2200157 4500008004100000245016800041210006900209300001400278490000700292100001700299700001800316700002400334700001700358700002100375856012000396 2000 eng d00aFossil fuel burning in Taylor Valley, southern Victoria Land, Antarctica: estimating the role of scientific activities on carbon and nitrogen reservoirs and fluxes0 aFossil fuel burning in Taylor Valley southern Victoria Land Anta a1659-16620 v341 aLyons, Berry1 aNezat, C., A.1 aWelch, Kathleen, A.1 aKottmeier, S1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/fossil-fuel-burning-taylor-valley-southern-victoria-land-antarctica-estimating-role00547nas a2200109 4500008004100000245012900041210006900170260002900239490001000268100003300278856012600311 1999 eng d00aFactors Affecting the Distribution and Dynamics of Bacterioplankton Biomass and Diversity in Taylor Valley Lakes, Antarctica0 aFactors Affecting the Distribution and Dynamics of Bacterioplank bMontana State University0 vPh.D.1 aTakacs-Vesbach, Cristina, D. uhttps://mcm.lternet.edu/content/factors-affecting-distribution-and-dynamics-bacterioplankton-biomass-and-diversity-taylor00662nas a2200121 4500008004100000245024500041210006900286300001200355490000700367100002300374700002100397856012200418 1998 eng d00aFluorescence Quenching in Phytoplankton of the McMurdo Dry Valley Lakes (Antarctica): Implications for the Structure and Function of the Photosynthetic Apparatus, in Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica0 aFluorescence Quenching in Phytoplankton of the McMurdo Dry Valle a241-2530 v721 aNeale, Patrick, J.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/fluorescence-quenching-phytoplankton-mcmurdo-dry-valley-lakes-antarctica-implications00517nas a2200133 4500008004100000245008000041210006900121100001800190700002400208700001900232700001900251700001800270856009500288 1998 eng d00aFrom the ground up: nematode ecology in bioassessment and ecosystem health0 aFrom the ground up nematode ecology in bioassessment and ecosyst1 aNiles, R., K.1 aFreckman, Diana, W.1 aBarker, K., R.1 aPederson, G.A.1 aWindham, G.L. uhttps://mcm.lternet.edu/content/ground-nematode-ecology-bioassessment-and-ecosystem-health00428nas a2200133 4500008004100000245004300041210004200084300001200126100001800138700001700156700002400173700002200197856007500219 1996 eng d00aFood-web dynamics and applied problems0 aFoodweb dynamics and applied problems a327-3361 aCrowder, L.B.1 aReagan, D.P.1 aFreckman, Diana, W.1 aWinemiller, Polis uhttps://mcm.lternet.edu/content/food-web-dynamics-and-applied-problems