scholarly journals Sediment Fluxes and Budgets in High-Latitude and High-Altitude Cold Environments

Eos ◽  
2007 ◽  
Vol 88 (52) ◽  
pp. 580 ◽  
Author(s):  
Scott Lamoureux ◽  
Achim Beylich ◽  
Armelle Decaulne
Keyword(s):  
High Altitude ◽  
High Latitude ◽  
Sediment Fluxes ◽  
Cold Environments

scholarly journals Seeds and Seedlings in a Changing World: A Systematic Review and Meta-Analysis from High Altitude and High Latitude Ecosystems

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 768
Author(s):  
Jerónimo Vázquez-Ramírez ◽  
Susanna E. Venn
Keyword(s):  
Climate Change ◽  
High Altitude ◽  
High Latitude ◽  
Seedling Establishment ◽  
Early Life History ◽  
Life Stages ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
Life History Stages ◽  
Early Snowmelt

The early life-history stages of plants, such as germination and seedling establishment, depend on favorable environmental conditions. Changes in the environment at high altitude and high latitude regions, as a consequence of climate change, will significantly affect these life stages and may have profound effects on species recruitment and survival. Here, we synthesize the current knowledge of climate change effects on treeline, tundra, and alpine plants’ early life-history stages. We systematically searched the available literature on this subject up until February 2020 and recovered 835 potential articles that matched our search terms. From these, we found 39 studies that matched our selection criteria. We characterized the studies within our review and performed a qualitative and quantitative analysis of the extracted meta-data regarding the climatic effects likely to change in these regions, including projected warming, early snowmelt, changes in precipitation, nutrient availability and their effects on seed maturation, seed dormancy, germination, seedling emergence and seedling establishment. Although the studies showed high variability in their methods and studied species, the qualitative and quantitative analysis of the extracted data allowed us to detect existing patterns and knowledge gaps. For example, warming temperatures seemed to favor all studied life stages except seedling establishment, a decrease in precipitation had a strong negative effect on seed stages and, surprisingly, early snowmelt had a neutral effect on seed dormancy and germination but a positive effect on seedling establishment. For some of the studied life stages, data within the literature were too limited to identify a precise effect. There is still a need for investigations that increase our understanding of the climate change impacts on high altitude and high latitude plants’ reproductive processes, as this is crucial for plant conservation and evidence-based management of these environments. Finally, we make recommendations for further research based on the identified knowledge gaps.

Lipid Oxidation during Thermogenesis in High-Altitude Deer Mice (Peromyscus maniculatus)

2021 ◽  
Author(s):  
Sulayman Aslan Lyons ◽  
Kevin B Tate ◽  
Kenneth Collins Welch ◽  
Grant B. McClelland
Keyword(s):  
Lipid Oxidation ◽  
Palmitic Acid ◽  
High Altitude ◽  
Deer Mice ◽  
Acid Oxidation ◽  
Cold Environments ◽  
Oxidation Rates ◽  
Low Altitude ◽  
Land Mammal ◽  
Specific Lipid

When at their maximum thermogenic capacity (cold-induced V̇O2max), small endotherms reach levels of aerobic metabolism as high, or even higher, than running V̇O2max. How these high rates of thermogenesis are supported by substrate oxidation is currently unclear. The appropriate utilization of metabolic fuels that could sustain thermogenesis over extended periods may be important for survival in cold environments, like high altitude. Previous studies show that high capacities for lipid use in high-altitude deer mice may have evolved in concert with greater thermogenic capacities. The purpose of this study was to determine how lipid utilization at both moderate and maximal thermogenic intensities may differ in high- and low- altitude deer mice, and strictly low-altitude white-footed mice. We also examined the phenotypic plasticity of lipid use after acclimation to cold hypoxia (CH), conditions simulating high altitude. We found that lipids were the primary fuel supporting both moderate and maximal rates of thermogenesis in both species of mice. Lipid oxidation increased 3-fold in mice from 30oC to 0oC, consistent with increases in oxidation of [13C]-palmitic acid. CH acclimation led to an increase in [13C]-palmitic acid oxidation at 30oC but did not affect total lipid oxidation. Lipid oxidation rates at cold-induced V̇O2max were two- to four-fold those at 0oC and increased further after CH acclimation, especially in high-altitude deer mice. These are the highest mass-specific lipid oxidation rates observed in any land mammal. Uncovering the mechanisms that allow for these high rates of oxidation will aid our understanding of the regulation of lipid metabolism.

Fluvial sediment fluxes response to modern climate change and human activities in the Tibetan Plateau and its margins

2021 ◽  
Author(s):  
Dongfeng Li ◽  
Xixi Lu ◽  
Ting Zhang
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Tibetan Plateau ◽  
Air Temperature ◽  
Human Activities ◽  
Sediment Flux ◽  
The Tibetan Plateau ◽  
Fluvial Sediment ◽  
Sediment Fluxes ◽  
Cold Environments

<p>Sediment flux in cold environments is a crucial proxy to link glacial, periglacial, and fluvial systems and highly relevant to hydropower operation, water quality, and the riverine carbon cycle. However, the long-term impacts of climate change and multiple human activities on sediment flux changes in cold environments remain insufficiently investigated due to the lack of monitoring and the complexity of the sediment cascade. Here we examine the multi-decadal changes in the in-situ observed fluvial sediment fluxes from two types of basins, namely, pristine basins and disturbed basins, in the Tibetan Plateau and its margins. The results show that the fluvial sediment fluxes in the pristine Tuotuohe headwater have substantially increased over the past three decades (i.e., a net increase of 135% from 1985–1997 to 1998–2017) due to the warming and wetting climate. We also quantify the relative impacts of air temperature and precipitation on the increases in the sediment fluxes with a novel attribution approach and finds that climate warming and intensified glacier-snow-permafrost melting is the primary cause of the increased sediment fluxes in the pristine cold environment (Tuotuohe headwater), with precipitation increase and its associated pluvial processes being the secondary driver. By contrast, the sediment fluxes in the downstream disturbed Jinsha River (southeastern margin of the Tibetan Plateau) exhibit a net increase of 42% from 1966-1984 to 1985-2010 mainly due to human activities such as deforestation and mineral extraction (contribution of 82%) and secondly because of climate change (contribution of 18%). Then the sediment fluxes dropped by 76% during the period of 2011-2015 because of the operations of six cascade reservoirs since 2010. In an expected warming and wetting climate for the region, we predict that the sediment fluxes in the pristine headwaters of the Tibetan Plateau will continue to increase throughout the 21st century, but the rising sediment fluxes from the Tibetan Plateau would be mostly trapped in its marginal reservoirs.</p><p>Overall, this work has provided the sedimentary evidence of modern climate change through robust observational sediment flux data over multiple decades. It demonstrates that sediment fluxes in pristine cold environments are more sensitive to air temperature and thermal-driven geomorphic processes than to precipitation and pluvial-driven processes. It also provides a guide to assess the relative impacts of human activities and climate change on fluvial sediment flux changes and has significant implications for water resources stakeholders to better design and manage the hydropower dams in a changing climate. Such findings may also have implications for other cold environments such as the Arctic, Antarctic, and other high mountainous basins.</p><p>Furthermore, this research is under the project of "Water and Sediment Fluxes Response to Climate Change in the Headwater Rivers of Asian Highlands" (supported by the IPCC and the Cuomo Foundation) and the project of "Sediment Load Responses to Climate Change in High Mountain Asia" (supported by the Ministry of Education of Singapore). Part of the results are also published in Li et al., 2018 Geomorphology, Li et al., 2020 Geophysical Research Letters, and Li et al., 2021 Water Resources Research.</p>

scholarly journals Statistics of high-altitude and high-latitude O<sup>+</sup> ion outflows observed by Cluster/CIS

2005 ◽  
Vol 23 (5) ◽  
pp. 1909-1916 ◽  
Author(s):  
S. Arvelius ◽  
M. Yamauchi ◽  
H. Nilsson ◽  
R. Lundin ◽  
Y. Hobara ◽  
...  
Keyword(s):  
High Altitude ◽  
High Latitude ◽  
Polar Region ◽  
High Latitudes ◽  
Latitudinal Distribution ◽  
Ion Outflow ◽  
Velocity Filter ◽  
Geocentric Distance ◽  
Magnetospheric Configuration And Dynamics ◽  
Magnetospheric Configuration

Abstract. The persistent outflows of O+ ions observed by the Cluster CIS/CODIF instrument were studied statistically in the high-altitude (from 3 up to 11 RE) and high-latitude (from 70 to ~90 deg invariant latitude, ILAT) polar region. The principal results are: (1) Outflowing O+ ions with more than 1keV are observed above 10 RE geocentric distance and above 85deg ILAT location; (2) at 6-8 RE geocentric distance, the latitudinal distribution of O+ ion outflow is consistent with velocity filter dispersion from a source equatorward and below the spacecraft (e.g. the cusp/cleft); (3) however, at 8-12 RE geocentric distance the distribution of O+ outflows cannot be explained by velocity filter only. The results suggest that additional energization or acceleration processes for outflowing O+ ions occur at high altitudes and high latitudes in the dayside polar region. Keywords. Magnetospheric physics (Magnetospheric configuration and dynamics, Solar wind-magnetosphere interactions)

scholarly journals Studying of solar-terrestrial connections in the dynamics of the surface atmospheric electric field

2020 ◽  
Vol 196 ◽  
pp. 01010
Author(s):  
Tatyana Kudrinskaya ◽  
Gennady Kupovykh ◽  
Anatoly Adzhiev ◽  
Bulat Zainetdinov
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Geomagnetic Activity ◽  
Field Intensity ◽  
High Latitude ◽  
Electric Field Intensity ◽  
Atmospheric Electric Field ◽  
Surface Atmosphere

The paper presents the results of the analysis of variations in the electric field intensity of the surface atmosphere obtained in high-latitude, high-altitude and lowland observation points, together with the parameters of solar and geomagnetic activity.

Biogeographical Characterisation of phytoplankton assemblages in high altitude, and high latitude European lakes

2009 ◽  
Vol 62 ◽  
pp. 55-75
Author(s):  
Monica Tolotti ◽  
Laura Forsström ◽  
Guiseppe Morabito ◽  
Bertha Thaler ◽  
Maya Stoyneva ◽  
...  
Keyword(s):  
High Altitude ◽  
High Latitude ◽  
Phytoplankton Assemblages

Seasonal variation of ozone vertical profiles form ExoMars TGO and comparison to water

2021 ◽  
Author(s):  
Manish R. Patel ◽  
Graham Seller ◽  
Jonathon Mason ◽  
James Holmes ◽  
Megan Brown ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
High Altitude ◽  
Relative Abundance ◽  
High Latitude ◽  
Dust Storm ◽  
Trace Gas ◽  
Line Of Sight ◽  
Vertical Profiles ◽  
Elevated Ozone ◽  
Vertical Distributions

&lt;p&gt;The Ultraviolet and Visible Spectrometer (UVIS) channel [1] of the Nadir and Occultation for Mars Discovery (NOMAD) instrument [2] aboard the ExoMars Trace Gas Orbiter has been making observations of the vertical, latitudinal and seasonal distributions of ozone.&amp;#160; Here, we present ~1.5 Mars Years (MY) of vertical profiles of ozone, from &lt;em&gt;L&lt;/em&gt;&lt;sub&gt;S&lt;/sub&gt; = 163&amp;#176; in MY34 to &lt;em&gt;L&lt;/em&gt;&lt;sub&gt;S&lt;/sub&gt; = 320&amp;#176; in MY35.&amp;#160; This period includes the occurrence of the MY34 Global Dust Storm. The relative abundance of both ozone and water (from coincident NOMAD measurements) increases with decreasing altitude below ~40&amp;#160;km at perihelion and at aphelion, localised decreases in ozone abundance exist between 25-35&amp;#160;km coincident with the location of modelled peak water abundances. High latitude (&gt; &amp;#177; 55&amp;#176;), high altitude (40-55&amp;#160;km) equinoctial ozone enhancements are observed in both hemispheres (&lt;em&gt;L&lt;/em&gt;&lt;sub&gt;S&lt;/sub&gt; ~350&amp;#8209;40&amp;#176;).&amp;#160; Morning terminator observations show elevated ozone abundances with respect to evening observations, most likely attributed to diurnal photochemical partitioning along the line of sight between ozone and O. The ozone retrievals presented here provide the most complete global description of Mars ozone vertical distributions to date as a function of season and latitude&lt;/p&gt;

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