Atmospheric Nitrate as a Potential Nutrient for Life on Mars

Nitrate is rich in Mars sediments owing to long-term atmospheric photolysis, oxidation, and deposition coupled with a lack of leaching via rainfall. The Atacama Desert in Chile, which is similarly dry and rich in nitrate deposits, is used as a Mars analog in this study to explore the potential effects of high nitrate levels on microbial growth. Seven study sites sampled across an aridity gradient in the Atacama Desert were categorized into 3 clusters – hyperarid, intermediate, and arid sites, as defined by major elements in the regolith, associated biomass, and precipitation. Intriguingly, the distribution of nitrate concentrations in the shallow subsurface suggests that the buildup of nitrate is not solely controlled by precipitation. Correlations of nitrate with SiO2/Al2O3 and grain sizes suggest that sedimentation rates are also important in controlling nitrate distribution. At arid sites receiving more than 10 mm/yr precipitation, rainfall shows a stronger impact on biomass than nitrate does. However, high nitrate to organic carbon ratios are generally beneficial to N assimilation as evidenced both by soil geochemistry and enriched culturing experiments. This study suggests that even in the absence of precipitation on contemporary Mars, the nitrate levels are sufficiently high to benefit potentially extant Martian microorganisms.

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Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System

Life ◽

10.3390/life9040079 ◽

2019 ◽

Vol 9 (4) ◽

pp. 79

Author(s):

Jianxun Shen ◽

Aubrey L. Zerkle ◽

Eva Stueeken ◽

Mark W. Claire

Keyword(s):

Atacama Desert ◽

Chemical Properties ◽

Soil Geochemistry ◽

Shallow Subsurface ◽

Shock Heating ◽

N Assimilation ◽

Mars Analog ◽

Study Sites ◽

Nitrate Distribution ◽

Physical And Chemical

Nitrate is common in Mars sediments owing to long-term atmospheric photolysis, oxidation, and potentially, impact shock heating. The Atacama Desert in Chile, which is the driest region on Earth and rich in nitrate deposits, is used as a Mars analog in this study to explore the potential effects of high nitrate levels on growth of extremophilic ecosystems. Seven study sites sampled across an aridity gradient in the Atacama Desert were categorized into 3 clusters—hyperarid, middle, and arid sites—as defined by essential soil physical and chemical properties. Intriguingly, the distribution of nitrate concentrations in the shallow subsurface suggests that the buildup of nitrate is not solely controlled by precipitation. Correlations of nitrate with SiO2/Al2O3 and grain sizes suggest that sedimentation rates may also be important in controlling nitrate distribution. At arid sites receiving more than 10 mm/yr precipitation, rainfall shows a stronger impact on biomass than nitrate does. However, high nitrate to organic carbon ratios are generally beneficial to N assimilation, as evidenced both by soil geochemistry and enriched culturing experiments. This study suggests that even in the absence of precipitation, nitrate levels on a more recent, hyperarid Mars could be sufficiently high to benefit potentially extant Martian microorganisms.

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Nest cameras do not affect nest survival in a meadow-nesting shorebird

Bird Conservation International ◽

10.1017/s0959270920000659 ◽

2020 ◽

pp. 1-10

Author(s):

VOLKER SALEWSKI ◽

LUIS SCHMIDT

Keyword(s):

Nest Survival ◽

Bird Species ◽

Conservation Strategies ◽

Survival Models ◽

Northern Germany ◽

Term Study ◽

Long Term Study ◽

Limosa Limosa ◽

Study Sites

Summary Identifying the fate of birds’ nests and the causes of breeding failure is often crucial for the development of conservation strategies for threatened species. However, collecting these data by repeatedly visiting nests might itself contribute to nest failure or bias. To solve this dilemma, automatic cameras have increasingly been used as a time-efficient means for nest monitoring. Here, we consider whether the use of cameras itself may influence hatching success of nests of the Black-tailed Godwit Limosa limosa at two long-term study sites in northern Germany. Annually between 2013 and 2019, cameras were used to monitor godwit nests. In 2014 and 2019, nests were randomly equipped with cameras or not, and nest survival checked independently of the cameras. Nest-survival models indicated that survival probabilities varied between years, sites and with time of the season, but were unaffected by the presence of cameras. Even though predation is the main cause of hatching failure in our study system, we conclude that predators did not learn to associate cameras with food either when the cameras were initially installed or after they had been used for several years. Cameras were thus an effective and non-deleterious tool to collect data for conservation in this case. As other bird species may react differently to cameras at their nests, and as other sets of predators may differ in their ability to associate cameras with food, the effect of cameras on breeding success should be carefully monitored when they are used in a new study system.

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Territorial governance of managed retreat in Sweden: addressing challenges

Journal of Environmental Studies and Sciences ◽

10.1007/s13412-021-00696-z ◽

2021 ◽

Author(s):

Gunnel Göransson ◽

Lisa Van Well ◽

David Bendz ◽

Per Danielsson ◽

Jim Hedfors

Keyword(s):

Climate Adaptation ◽

Governance Framework ◽

Case Study Site ◽

Feasible Option ◽

Flexible Planning ◽

Barriers And Opportunities ◽

Study Sites ◽

Inland Flooding

AbstractMany climate adaptation options currently being discussed in Sweden to meet the challenge of surging seas and inland flooding advocate holding the line through various hard and soft measures to stabilize the shoreline, while managed retreat is neither considered as feasible option nor has it been explicitly researched in Sweden. However, failure to consider future flooding from climate change in municipal planning may have dangerous and costly consequences when the water does come. We suggest that managed retreat practices are challenging in Sweden, not only due to public opinions but also because of a deficit of uptake of territorial knowledge by decision-makers and difficulties in realizing flexible planning options of the shoreline. A territorial governance framework was used as a heuristic to explore the challenges to managed retreat in four urban case studies (three municipalities and one county) representing different territorial, hydrological and oceanographic environments. This was done through a series of participatory stakeholder workshops. The analysis using a territorial governance framework based on dimensions of coordination, integration, mobilization, adaptation and realization presents variations in how managed retreat barriers and opportunities are perceived among case study sites, mainly due to the differing territorial or place-based challenges. The results also indicate common challenges regardless of the case study site, including coordination challenges and unclear responsibility, the need for integrated means of addressing goal conflicts and being able to adapt flexibly to existing regulations and plans. Yet rethinking how managed retreat could boost community resilience and help to implement long-term visions was seen as a way to deal with some of the territorial challenges.

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A method for simulating risk profiles of wheat yield in data-sparse conditions

The Journal of Agricultural Science ◽

10.1017/s0021859621000253 ◽

2021 ◽

pp. 1-12

Author(s):

G. Bracho-Mujica ◽

P.T. Hayman ◽

V.O. Sadras ◽

B. Ostendorf

Keyword(s):

Reference Site ◽

Climate Impacts ◽

Weather Data ◽

Climate Data ◽

High Quality ◽

Risk Profiles ◽

Record Length ◽

Daily Weather Data ◽

Study Sites

Abstract Process-based crop models are a robust approach to assess climate impacts on crop productivity and long-term viability of cropping systems. However, these models require high-quality climate data that cannot always be met. To overcome this issue, the current research tested a simple method for scaling daily data and extrapolating long-term risk profiles of modelled crop yields. An extreme situation was tested, in which high-quality weather data was only available at one single location (reference site: Snowtown, South Australia, 33.78°S, 138.21°E), and limited weather data was available for 49 study sites within the Australian grain belt (spanning from 26.67 to 38.02°S of latitude, and 115.44 to 151.85°E of longitude). Daily weather data were perturbed with a delta factor calculated as the difference between averaged climate data from the reference site and the study sites. Risk profiles were built using a step-wise combination of adjustments from the most simple (adjusted series of precipitation only) to the most detailed (adjusted series of precipitation, temperatures and solar radiation), and a variable record length (from 10 to 100 years). The simplest adjustment and shortest record length produced bias of modelled yield grain risk profiles between −10 and 10% in 41% of the sites, which increased to 86% of the study sites with the most detailed adjustment and longest record (100 years). Results indicate that the quality of the extrapolation of risk profiles was more sensitive to the number of adjustments applied rather than the record length per se.

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Worldwide variations in artificial skyglow

Scientific Reports ◽

10.1038/srep08409 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 79

Author(s):

Christopher C. M. Kyba ◽

Kai Pong Tong ◽

Jonathan Bennie ◽

Ignacio Birriel ◽

Jennifer J. Birriel ◽

...

Keyword(s):

Monitoring Program ◽

Artificial Light ◽

Clear Sky ◽

International Monitoring ◽

Sky Brightness ◽

Ground Truthing ◽

Study Sites ◽

Night Sky Brightness ◽

Key Questions

Abstract Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.

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Ignimbrite as a substrate for endolithic life in the hyper-arid Atacama Desert: Implications for the search for life on Mars

Icarus ◽

10.1016/j.icarus.2012.06.009 ◽

2013 ◽

Vol 224 (2) ◽

pp. 334-346 ◽

Cited By ~ 34

Author(s):

Jacek Wierzchos ◽

Alfonso F. Davila ◽

Octavio Artieda ◽

Beatriz Cámara-Gallego ◽

Asunción de los Ríos ◽

...

Keyword(s):

Atacama Desert ◽

Life On Mars

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A method for reconstructing past lake water phosphorus concentrations using sediment geochemical records

Journal of Paleolimnology ◽

10.1007/s10933-021-00174-0 ◽

2021 ◽

Author(s):

Madeleine Moyle ◽

John F. Boyle

Keyword(s):

Lake Water ◽

Water Quality Monitoring ◽

Specific Reference ◽

Site Specific ◽

Burial Rate ◽

Steady State Model ◽

Sediment Records ◽

Current Water ◽

Study Sites

AbstractAn existing steady state model of lake phosphorus (P) budgets has been adapted to allow reconstruction of long-term average historic lake water total phosphorus (TP) concentrations using lake sediment records of P burial. This model can be applied without site-specific parameterisation, thus potentially having universal application. In principle, it is applicable at any site where there is both a sediment P burial record and knowledge of the current water budget, although we advise caution applying it to problematic sediment records. Tested at six published case study sites, modelled lake water TP concentrations agree well with water-quality monitoring data, and limited testing finds good agreement with wholly independent diatom inferred lake water TP. Our findings, together with a review of the literature, suggest that well preserved lake sediments can usefully record a long-term average P burial rate from which the long-term mean lake water TP can be reliably estimated. These lake water TP reconstructions can provide meaningful site-specific reference values to support decision making in lake eutrophication management, including establishing targets for lake restoration.

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Big Benefits from Experimental Watersheds

Eos ◽

10.1029/2021eo154161 ◽

2021 ◽

Vol 102 ◽

Author(s):

Terri Cook

Keyword(s):

Land Management ◽

Agricultural Research ◽

Conservation Practices ◽

Term Study ◽

Long Term Study ◽

Global Land ◽

Study Sites ◽

Management And Conservation ◽

Experimental Watersheds

Scientific insights from the Agricultural Research Service’s long-term study sites underpin dozens of models and research methods that guide global land management and conservation practices.

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Long-Term Impacts of Weather Conditions on Indoor Radon Concentration Measurements in Switzerland

Atmosphere ◽

10.3390/atmos13010092 ◽

2022 ◽

Vol 13 (1) ◽

pp. 92

Author(s):

Joan Frédéric Rey ◽

Stéphane Goyette ◽

Mauro Gandolla ◽

Martha Palacios ◽

Fabio Barazza ◽

...

Keyword(s):

Radon Concentration ◽

Indoor Radon ◽

Weather Conditions ◽

Indoor Environments ◽

Indoor Radon Concentration ◽

Prone Area ◽

Building Characteristics ◽

Study Sites ◽

Radon Measurements

Radon is a natural and radioactive gas that can accumulate in indoor environments. Indoor radon concentration (IRC) is influenced, among other factors, by meteorology, which is the subject of this paper. Weather parameters impact indoor radon levels and have already been investigated, but rarely in Switzerland. Moreover, there is a strong need for a better understanding of the radon behaviour inside buildings in Switzerland for public health concerns as Switzerland is a radon prone area. Based on long-term, continuous, and hourly radon measurements, radon distributions classified according to different weather event definitions were investigated and then compared at three different study sites in Western Switzerland. Outdoor temperature influences the most indoor radon, and it is globally anti-correlated. Wind influences indoor radon, but it strongly depends on intensity, direction, and building characteristics. Precipitation influences periodically indoor radon levels relatively to their intensity. Atmospheric pressure and relative humidity do not seem to be huge determinants on IRC. Our results are in line with previous findings and provide a vivid example in Western Switzerland. This paper underlines the different influence complexities of radon, and the need to communicate about it within the broader public and with construction professionals, to raise awareness.

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April: Six Degrees of Connectivity

Saving the Dammed ◽

10.1093/oso/9780190943523.003.0007 ◽

2019 ◽

Author(s):

Ellen Wohl

Keyword(s):

Green Algae ◽

Term Study ◽

Beaver Ponds ◽

Side Channels ◽

Long Term Study ◽

Deep Shade ◽

Northern Edge ◽

Study Sites ◽

Dark Green

By late April, the snow is gone from the beaver meadow. The promises of March are starting to be fulfilled: insects are on the wing, some of the willows have furry catkins along their branches, and fish jump from the quiet waters of the beaver ponds. I can no longer easily get around the beaver meadows on foot unless I wear chest waders. The sound of the beaver meadow in March was primarily wind. By April, the sound is primarily moving water. The water gurgles, shushes, and whispers. In another month it will roar with the melting snows. Another three miles up the creek valley and 1,500 feet higher, one of my long-term study sites still lies under 6 feet of snow, but in the meadow I see only one patch of tenacious snow-ice in the deep shade beneath a spruce along the northern edge of the meadow. I know that snow will still fall here during late spring storms, but it will melt quickly. March felt on the cusp, as if it could as easily tip toward winter or spring. Late April is definitely spring headed toward summer. The beaver meadow remains a riverscape more brown and tan than green. The willows are still leafless, although some of the branch tips are turning pale yellow-green and others seem to be taking on a more vivid orange hue. I can see the leaf buds starting to swell. The grass has just begun to grow in dark green tips steadily forcing their way through the thick mat of last year’s dead stems. Clusters of new leaves on low-growing wintergreen are the only other sign of green outside of the channels. Some of the smaller side channels are thick with emerald green algae undulating slowly in the current. A stonefly lands on my hand. Its slender, dark gray body seems surprisingly delicate for a creature that has hatched into the vagaries of April air, with its potential for blasting winds and sudden snow squalls.

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