scholarly journals The physical basis for ecohydrologic separation: the roles of soil hydraulics and climate

2021 ◽  
Author(s):  
Catherine Finkenbiner ◽  
Stephen Good ◽  
Jacqueline Brooks ◽  
Scott Allen ◽  
Salini Sasidharan
Keyword(s):  
Soil Water ◽  
Field Measurements ◽  
Isotope Ratios ◽  
Critical Zone ◽  
Subsurface Water ◽  
Soil Physics ◽  
Local Conditions ◽  
Climate Conditions ◽  
Transport Dynamics ◽  
Solute Fluxes

Abstract The degree of water mixing in the critical zone is under intense debate. Field measurements of isotope ratios indicate varying degrees of separation between pools of water that supply streams and vegetation. The exact physical mechanisms behind ecohydrologic separation are unknown, but local conditions such as soil heterogeneities likely influence the extent of mixing and separation of subsurface water pools. Using a well-established soil physics model, we simulated if isotopic separations occur within 650 distinct configurations of soil properties, climatologies, and mobile/immobile soil-water domains. Simulations demonstrated separations in isotope ratios between storage and drainage waters during periods of high precipitation, soil water content, and drainage. Separations grew with larger immobile domains and, to a lesser extent, higher mobile-immobile transfer rates. Across soil types and climates, lower saturated hydraulic conductivity and higher rainfall rates amplified isotopic differences, illustrating how mobile and immobile domains interact with local conditions to physically result in subsurface separations. These results show how different critical-zone solute fluxes can be generated by representing contrasting transport dynamics in distinct domains across a range of soils and climate conditions.

scholarly journals Agriculture and land use in the North of Russia: Case study of Karelia and Yakutia

2020 ◽  
Vol 12 (1) ◽  
pp. 1497-1511
Author(s):  
Alexey Naumov ◽  
Varvara Akimova ◽  
Daria Sidorova ◽  
Mikhail Topnikov
Keyword(s):  
Land Use ◽  
Agricultural Development ◽  
Agricultural Land ◽  
Geographical Location ◽  
Special Role ◽  
Sources Of Information ◽  
Local Conditions ◽  
Climate Conditions ◽  
The North ◽  
The Republic

AbstractDespite harsh climate, agriculture on the northern margins of Russia still remains the backbone of food security. Historically, in both regions studied in this article – the Republic of Karelia and the Republic of Sakha (Yakutia) – agricultural activities as dairy farming and even cropping were well adapted to local conditions including traditional activities such as horse breeding typical for Yakutia. Using three different sources of information – official statistics, expert interviews, and field observations – allowed us to draw a conclusion that there are both similarities and differences in agricultural development and land use of these two studied regions. The differences arise from agro-climate conditions, settlement history, specialization, and spatial pattern of economy. In both regions, farming is concentrated within the areas with most suitable natural conditions. Yet, even there, agricultural land use is shrinking, especially in Karelia. Both regions are prone to being affected by seasonality, but vary in the degree of its influence. Geographical location plays special role, and weaknesses caused by remoteness to some extent become advantage as in Yakutia. Proximity effect is controversial. In Karelia, impact of neighboring Finland is insignificant compared with the nearby second Russian city – Saint Petersburg.

Non-invasive field measurements of soil water content using a pulsed 14MeV neutron generator

2012 ◽  
Vol 120 ◽  
pp. 130-136 ◽  
Author(s):  
S. Mitra ◽  
L. Wielopolski ◽  
R. Omonode ◽  
J. Novak ◽  
J. Frederick ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Neutron Generator ◽  
Field Measurements ◽  
Non Invasive ◽  
14Mev Neutron

scholarly journals Robust, spatially scanning, open-path TDLAS hygrometer using retro-reflective foils for fast tomographic 2-D water vapour concentration field measurements

2014 ◽  
Vol 7 (12) ◽  
pp. 12827-12849 ◽  
Author(s):  
A. Seidel ◽  
S. Wagner ◽  
A. Dreizler ◽  
V. Ebert
Keyword(s):  
Water Vapour ◽  
Single Channel ◽  
Greenhouse Gas Emission ◽  
Concentration Field ◽  
Field Measurements ◽  
Tunable Diode Laser ◽  
Environmental Research ◽  
Soil Physics ◽  
Water Vapour Concentration ◽  
Vapour Concentration

Abstract. We have developed a fast, spatially direct scanning tunable diode laser absorption spectrometer (dTDLAS) that combines four polygon-mirror based scanning units with low-cost retro-reflective foils. With this instrument, tomographic measurements of absolute 2-D water vapour concentration profiles are possible without any calibration using a reference gas. A spatial area of 0.8 m × 0.8 m was covered, which allows for application in soil physics, where greenhouse gas emission from certain soil structures shall be monitored. The whole concentration field was measured with up to 2.5 Hz. In this paper, we present the setup and spectroscopic performance of the instrument regarding the influence of the polygon rotation speed and mode on the absorption signal. Homogeneous H2O distributions were measured and compared to a single channel, bi-static reference TDLAS spectrometer for validation of the instrument. Good accuracy and precision with errors of less than 6% of the absolute concentration and length and bandwidth normalized detection limits of up to 1.1 ppmv · m · √Hz−1 were achieved. The spectrometer is a robust and easy to set up instrument for tomographic reconstructions of 2-D-concentration fields that can be considered a good basis for future field measurements in environmental research.

Environmental Degradation, Tropical Diseases, and Economic Development

2021 ◽  
Author(s):  
John Luke Gallup
Keyword(s):  
Climate Change ◽  
Economic Development ◽  
Environmental Degradation ◽  
Global Climate ◽  
Life Cycles ◽  
Tropical Diseases ◽  
Local Conditions ◽  
Climate Conditions ◽  
And Control ◽  
The Impact

It’s complicated. Tropical diseases have unusually intricate life cycles because most of them involve not only a human host and a pathogen, but also a vector host. The diseases are predominantly tropical due to their sensitivity to local ecology, usually due to the vector organism. The differences between the tropical diseases mean that they respond to environmental degradation in various ways that depend on local conditions. Urbanization and water pollution tend to limit malaria, but deforestation and dams can exacerbate malaria and schistosomiasis. Global climate change, the largest environmental change, will likely extend the range of tropical climate conditions to higher elevations and near the limits of the tropics, spreading some diseases, but will make other areas too dry or hot for the vectors. Nonetheless, the geographical range of tropical diseases will be primarily determined by public health efforts more than climate. Early predictions that malaria will spread widely because of climate change were flawed, and control efforts will probably cause it to diminish further. The impact of human disease on economic development is hard to pin down with confidence. It may be substantial, or it may be misattributed to other influences. A mechanism by which tropical disease may have large development consequences is its deleterious effects on the cognitive development of infants, which makes them less productive throughout their lives.

scholarly journals Interannual and Seasonal Variations in Ecosystem Transpiration and Water Use Efficiency in a Tropical Rainforest

Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 14 ◽  
Author(s):  
Maricar Aguilos ◽  
Clément Stahl ◽  
Benoit Burban ◽  
Bruno Hérault ◽  
Elodie Courtois ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Seasonal Variations ◽  
Radiation Effects ◽  
Global Radiation ◽  
Climate Conditions ◽  
Carbon Cycles ◽  
Use Efficiency ◽  
The Impact

Warmer and drier climates over Amazonia have been predicted for the next century with expected changes in regional water and carbon cycles. We examined the impact of interannual and seasonal variations in climate conditions on ecosystem-level evapotranspiration (ET) and water use efficiency (WUE) to determine key climatic drivers and anticipate the response of these ecosystems to climate change. We used daily climate and eddyflux data recorded at the Guyaflux site in French Guiana from 2004 to 2014. ET and WUE exhibited weak interannual variability. The main climatic driver of ET and WUE was global radiation (Rg), but relative extractable water (REW) and soil temperature (Ts) did also contribute. At the seasonal scale, ET and WUE showed a modal pattern driven by Rg, with maximum values for ET in July and August and for WUE at the beginning of the year. By removing radiation effects during water depleted periods, we showed that soil water stress strongly reduced ET. In contrast, drought conditions enhanced radiation-normalized WUE in almost all the years, suggesting that the lack of soil water had a more severe effect on ecosystem evapotranspiration than on photosynthesis. Our results are of major concern for tropical ecosystem modeling because they suggest that under future climate conditions, tropical forest ecosystems will be able to simultaneously adjust CO2 and H2O fluxes. Yet, for tropical forests under future conditions, the direction of change in WUE at the ecosystem scale is hard to predict, since the impact of radiation on WUE is counterbalanced by adjustments to soil water limitations. Developing mechanistic models that fully integrate the processes associated with CO2 and H2O flux control should help researchers understand and simulate future functional adjustments in these ecosystems.

scholarly journals Assessment of Siltation Processes of the Koronowski Reservoir in the Northern Polish Lowland Based on Bathymetry and Empirical Formulas

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1681 ◽  
Author(s):  
Dawid Szatten ◽  
Michał Habel ◽  
Luisa Pellegrini ◽  
Michael Maerker
Keyword(s):  
Flood Control ◽  
Field Measurements ◽  
Suspended Sediments ◽  
River System ◽  
Empirical Formulas ◽  
Filtration Method ◽  
Transport Dynamics ◽  
Sediment Budgets ◽  
The Impact ◽  
Artificial Reservoirs

Artificial reservoirs have an important role in water management of river systems in terms of flood control, water supply and sediment budgeting. Therefore, it is important to maximize the time of their effective functioning. Sediment budgeting mainly depends on sediment transport dynamics. This article illustrates the impact of the Koronowski Reservoir on suspended sediments transported by the Brda River. The river system and the reservoir represent a typical lowland river environment. Our research is based on hydrological and sedimentological investigations on the reservoir and the river system. Field measurements were used to create the respective hydrological and sediment budgets. Moreover, we carried out bathymetric measurements to generate present day bathymetry and to calculate the reservoir’s capacity. We assessed the silting of the reservoir following the approaches proposed by Goncarov and Stonawski. We show that the size and dynamics of suspended sediments are mainly determined by the hydrological conditions. Moreover, we illustrate that the suspended sediment measurements made with the filtration method correlate with the nephelometric results. Generally, we show that the Koronowski Reservoir is mainly filled up by suspended sediments. We further illustrate that the level of siltation estimated with the empirical formulas deviates significantly from calculations made by bathymetric measurements.

scholarly journals Biogenic isoprenoid emissions under drought stress: different responses for isoprene and terpenes

2019 ◽  
Vol 16 (23) ◽  
pp. 4627-4645 ◽  
Author(s):  
Boris Bonn ◽  
Ruth-Kristina Magh ◽  
Joseph Rombach ◽  
Jürgen Kreuzwieser
Keyword(s):  
Drought Stress ◽  
Soil Water ◽  
Water Availability ◽  
Plant Protection ◽  
Soil Water Availability ◽  
Climate Feedback ◽  
Severe Drought ◽  
Emission Rates ◽  
Plant Structure ◽  
Climate Conditions

Abstract. Emissions of volatile organic compounds (VOCs) by biogenic sources depend on different environmental conditions. Besides temperature and photosynthetic active radiation (PAR), the available soil water can be a major factor controlling the emission flux. This factor is expected to become more important under future climate conditions, including prolonged drying–wetting cycles. In this paper we use results of available studies on different tree types to set up a parameterization describing the influence of soil water availability (SWA) on different isoprenoid emission rates. Investigating SWA effects on isoprene (C5H8), monoterpene (C10H16) and sesquiterpene (C15H24) emissions separately, it is obvious that different plant processes seem to control the individual emission fluxes, providing a measure to which plants can react to stresses and interact. The SWA impact on isoprene emissions is well described by a biological growth type curve, while the sum of monoterpenes displays a hydraulic conductivity pattern reflecting the plant's stomata opening. However, emissions of individual monoterpene structures behave differently to the total sum, i.e., the emissions of some increase, whereas others decline at decreasing SWA. In addition to a rather similar behavior to that of monoterpene emissions, total sesquiterpene fluxes of species adapted to drought stress tend to reveal a rise close to the wilting point, protecting against oxidative damages. Considering further VOCs as well, the total sum of VOCs tends to increase at the start of severe drought conditions until resources decline. In contrast to declining soil water availability, OH and ozone reactivity are enhanced. Based on these observations, a set of plant protection mechanisms are displayed for fighting drought stress and imply notable feedbacks on atmospheric processes such as ozone, aerosol particles and cloud properties. With increasing lengths of drought periods, declining storage pools and plant structure effects yield different emission mixtures and strengths. This drought feedback effect is definitely worth consideration in climate feedback descriptions and for accurate climate predictions.

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