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Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 131
Author(s):  
Zohreh Safdari ◽  
Hossein Nahavandchi ◽  
Gholamreza Joodaki

Iran is experiencing significant water challenges that have now turned water security into a national priority. By estimating secular trend groundwater storage in Iran between 2002 and 2017, we see that there is an intensive negative trend, even −4400 Mm3 in some areas. These estimations show shifting in the climate and extra extraction from aquifers for agricultural use in some areas in Iran. The secular trend of groundwater storage changes across the whole of Iran inferred from observation well data is −20.08 GT/yr. The secular trends of GWS changes based on observation well data are: −11.55 GT/yr for the Central Plateau basin, −3.60 GT/yr for the Caspian Sea basin, −3.0 GT/yr for the Persian Gulf and Oman Sea basin, −0.53 GT/yr for the Urmieh Lake basin, −0.57 GT/yr for the Eastern Boundary basin, and −0.83 GT/yr for the Gharaghom basin. The most depleted sub-basin (Kavir Markazi) has secular trends of GWS changes of −4.503 GT/yr. This study suggests that groundwater depletion is the largest single contributor to the observed negative trend of groundwater storage changes in Iran, the majority of which occurred after the drought in 2007. The groundwater loss that has been accrued during the study period is particularly alarming for Iran, which is already facing severe water scarcity.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yu Liang ◽  
Cheng Quan ◽  
Yongxiang Li ◽  
Weiguo Liu ◽  
Zhonghui Liu

Knowledge of paleolake evolution is highly important for understanding the past hydroclimate regime on the Tibetan Plateau and associated forcing mechanisms. However, the hydrological history of paleolakes on the central plateau, the core region of the plateau, remains largely inconclusive. Here we present new biomarker records from lacustrine deposits of the Lunpori section in the Lunpola Basin to reconstruct detailed lake-level fluctuations during the mid-Miocene. A set of n-alkane indexes, including the proportion of aquatic macrophytes (Paq), average chain length and carbon preference index as well as the content of n-alkanes, vary substantially and consistently throughout the studied interval. Our results altogether show relatively low lake level at ∼16.3–15.5 Ma and high lake level before and after the interval, which is in line with the lithological observations in the section. Further comparison with existing regional and global temperature records suggests that lake level fluctuations can be largely linked to global climatic conditions during the mid-Miocene, with lake expansion during relatively warm periods and vice versa. Therefore, we infer that global climatic changes might have controlled the lake-level fluctuations in this region during the mid-Miocene, whereas the tectonic uplift likely played a subordinate role on this timescale.


Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 676
Author(s):  
Alma E. García-Morales ◽  
Omar Domínguez-Domínguez ◽  
Manuel Elías-Gutiérrez

The correct identification of species is an essential step before any study on biodiversity, ecology or genetics. Keratella is a genus with a predominantly temperate distribution and with several species being endemics or restricted geographically. Its diversity may be underestimated considering the confusing taxonomy of species complexes such as K. cochlearis. In this study, we examined genetic diversity and morphology among some Keratella populations from Mexico in order to determine if these populations represent different species. We analyzed a dataset of previously published and newly generated sequences of the mitochondrial COI gene and the nuclear ITS1 marker. We conducted phylogenetic analyses and applied three methods of species delimitation (ABGD, PTP and GMYC) to identify evolutionary significant units (ESUs) equivalent to species. Morphological analyses were conducted through scanning electron microscope (SEM) and morphometry under a compound microscope. In the present study, three new species Keratella cuitzeiensis sp. nov., Keratella huapanguensis sp. nov., and Keratella albertae sp. nov., are formally described. These species were collected in high-altitude water bodies located in the Central Plateau of Mexico. Combining DNA results through COI and ITS1 molecular markers and morphology it was possible to confirm the identity of the new species.


2021 ◽  
Vol 194 (1) ◽  
Author(s):  
Hannah Wey ◽  
Daniel Hunkeler ◽  
Wolf-Anno Bischoff ◽  
Else K. Bünemann

AbstractDeterioration of groundwater quality due to nitrate loss from intensive agricultural systems can only be mitigated if methods for in-situ monitoring of nitrate leaching under active farmers’ fields are available. In this study, three methods were used in parallel to evaluate their spatial and temporal differences, namely ion-exchange resin-based Self-Integrating Accumulators (SIA), soil coring for extraction of mineral N (Nmin) from 0 to 90 cm in Mid-October (pre-winter) and Mid-February (post-winter), and Suction Cups (SCs) complemented by a HYDRUS 1D model. The monitoring, conducted from 2017 to 2020 in the Gäu Valley in the Swiss Central Plateau, covered four agricultural fields. The crop rotations included grass-clover leys, canola, silage maize and winter cereals. The monthly resolution of SC samples allowed identifying a seasonal pattern, with a nitrate concentration build-up during autumn and peaks in winter, caused by elevated water percolation to deeper soil layers in this period. Using simulated water percolation values, SC concentrations were converted into fluxes. SCs sampled 30% less N-losses on average compared to SIA, which collect also the wide macropore and preferential flows. The difference between Nmin content in autumn and spring was greater than nitrate leaching measured with either SIA or SCs. This observation indicates that autumn Nmin was depleted not only by leaching but also by plant and microbial N uptake and gaseous losses. The positive correlation between autumn Nmin content and leaching fluxes determined by either SCs or SIA suggests autumn Nmin as a useful relative but not absolute indicator for nitrate leaching. In conclusion, all three monitoring techniques are suited to indicate N leaching but represent different transport and cycling processes and vary in spatio-temporal resolution. The choice of monitoring method mainly depends (1) on the project’s goals and financial budget and (2) on the soil conditions. Long-term data, and especially the combination of methods, increase process understanding and generate knowledge beyond a pure methodological comparison.


2021 ◽  
Author(s):  
◽  
Rebecca Joan O'Donnell

<p>The aim of this study was to improve our understanding of Quaternary glaciations in Tasmania, and to assess their climatic significance. During the Quaternary, Tasmania experienced ice cap development in the West Coast Range and Central Plateau, with smaller cirque and valley glaciers developing on surrounding mountains. Geomorphic evidence indicates at least four glacial advances occurred. A 500 m resolution, three-dimensional thermomechanical ice-sheet model was used to reconstruct and simulate these glacier fluctuations. The model, while a simplification of reality, provided a framework in which to understand the genesis of contemporary landforms and former glacial climate conditions in Tasmania. Input specifications of basal topography, temperature and precipitation were required, with the latter two interpolated from present-day datasets. Numerous experiments were carried out, involving systematic alterations to temperature and precipitation, basal sliding and atmospheric temperature lapse-rates. Modelled output was compared to empirical evidence with the aim of optimizing the parameters (temperature, precipitation) from which model mismatch was minimised. An annual temperature reduction of 6' C is required for glaciers to form in Tasmania. When temperatures cool beyond this threshold, an ice mass develops over the Central Highlands, Central Plateau, West Coast Range and other mountains. In all but the most extensive glaciations, the Central Plateau ice field consists of a relatively thin carapace of ice, and the thickest and most dynamic glaciers develop in the deep valleys of the Central Highlands. The model shows that ice readily flows down the west-facing valleys from the Central Highlands to join with West Coast Range glaciers. A temperature reduction between 7 and 9' C, with corresponding regional precipitation changes of between +/-50% and an increase in orographic precipitation is required to simulate the Last Glacial Maximum (LGM) ice cover. Earlier glacial advances require larger coolings of up to 11.25' C depending on the regional precipitation conditions prescribed. Mismatches between geomorphic evidence and modelled reconstructions probably result from model grid size issues and parameters not accommodated by the model such as wind-blown snow redistribution. This means that temperature reductions derived from the model may have been overestimated. Despite these limitations, reconstructed temperatures compare well to some multi-proxy palaeo-temperature records from Tasmania, although the cooling identified was larger than that recorded in nearby ocean sediments.</p>


2021 ◽  
Vol 22 (3) ◽  
pp. 353-361
Author(s):  
NAVEEN P. SINGH ◽  
BHAWNA ANAND ◽  
K.V. RAO ◽  
RANJITH P.C.

Using large-scale district-level data, the study examined the impact of climate change on crop yields during the period 1966-2011and predictsthe likely changes in yield sacross agro-climatic zones in Plateau Region. The future projections reveal that by 2080s, cotton yield is expected to decline by 7.18 percent in Western Plateau & Hills.By the end of the century, sorghum yield is projected to decline up to 19 percent in Central Plateau & Hills and increase by 18 percent in Western Plateau & Hills. Under midterm period, rapeseed & mustard yield is likely to reduce by 3.44 percent in Western Plateau & Hills. By 2050s maize yield is expected to reduce by 3.33 percent in Central Plateau & Hills. By 2080s, wheat yield is projected to decline by 5.44, percent in SouthernPlateau & Hills. The results suggest that impact of climate change on crop yield varies across regions, hence it is pertinent to formulate adaptation strategies and farm practices suitable to the crop and location specific needs that mitigate the likely exposure of food production and livelihoods to climate variations.


2021 ◽  
Author(s):  
◽  
Rebecca Joan O'Donnell

<p>The aim of this study was to improve our understanding of Quaternary glaciations in Tasmania, and to assess their climatic significance. During the Quaternary, Tasmania experienced ice cap development in the West Coast Range and Central Plateau, with smaller cirque and valley glaciers developing on surrounding mountains. Geomorphic evidence indicates at least four glacial advances occurred. A 500 m resolution, three-dimensional thermomechanical ice-sheet model was used to reconstruct and simulate these glacier fluctuations. The model, while a simplification of reality, provided a framework in which to understand the genesis of contemporary landforms and former glacial climate conditions in Tasmania. Input specifications of basal topography, temperature and precipitation were required, with the latter two interpolated from present-day datasets. Numerous experiments were carried out, involving systematic alterations to temperature and precipitation, basal sliding and atmospheric temperature lapse-rates. Modelled output was compared to empirical evidence with the aim of optimizing the parameters (temperature, precipitation) from which model mismatch was minimised. An annual temperature reduction of 6' C is required for glaciers to form in Tasmania. When temperatures cool beyond this threshold, an ice mass develops over the Central Highlands, Central Plateau, West Coast Range and other mountains. In all but the most extensive glaciations, the Central Plateau ice field consists of a relatively thin carapace of ice, and the thickest and most dynamic glaciers develop in the deep valleys of the Central Highlands. The model shows that ice readily flows down the west-facing valleys from the Central Highlands to join with West Coast Range glaciers. A temperature reduction between 7 and 9' C, with corresponding regional precipitation changes of between +/-50% and an increase in orographic precipitation is required to simulate the Last Glacial Maximum (LGM) ice cover. Earlier glacial advances require larger coolings of up to 11.25' C depending on the regional precipitation conditions prescribed. Mismatches between geomorphic evidence and modelled reconstructions probably result from model grid size issues and parameters not accommodated by the model such as wind-blown snow redistribution. This means that temperature reductions derived from the model may have been overestimated. Despite these limitations, reconstructed temperatures compare well to some multi-proxy palaeo-temperature records from Tasmania, although the cooling identified was larger than that recorded in nearby ocean sediments.</p>


Author(s):  
N. Mishra ◽  
K. C. Sahoo ◽  
M. Ray ◽  
P. K. Majhi ◽  
S. Das ◽  
...  

Aim: To identify the proper variety and suitable date of planting of potato for North Central Plateau Zone (NCPZ) of Odisha. Study Design: The experiment was laid in a Factorial Randomized Block Design (FRBD) with three replications. Place and Duration of Study: The field experiment was carried out at Field Experimental Block, Regional research and Technology Transfer Station (RRTTS), Keonjhar, Odisha University of Agriculture and Technology, Odisha. The investigation was conducted during rabi-2015-16 and rabi-2016-17. Methodology: There were four high yielding potato genotypes used as sub-factor for the study such as V1: Kufri Jyoti, V2: Kufri Surya, V3: Kufri Ashoka and V4: Kufri Pukhraj. The materials were planted in three different dates (D1: 15th November, D2: 25th November and D3: 5th December) as main-factor to identify the superior variety with suitable dates of planting. Results: The results of pooled analysis of variance (ANOVA) shown that the genotypes had significant differences for the dates of planting on yield. Higher tuber yield was recorded in the variety Kufri Pukhraj in both rabi-2015-16 (28.37 t ha-1) and rabi-2016-17 (35.53 t ha-1) along with higher mean yield (31.95 t ha-1). All the varieties have higher yield when planted on D1 (15th November) as compared to the other two date of planting. Conclusion: The varietal and environmental variations as well as their interaction had a considerable influence on yield and its attributes. In this investigation, Kufri Pukhraj was identified as higher yielder and 15th November was found best suitable planting date for north central plateau zone of Odisha, as this date given higher yield as compared to the other two dated of plating. Therefore, if a specific window of date of planting can be ascertained to the farmers of this region then it would help to cultivate potato exactly when the climatic conditions are favorable for its growth and ultimately to get a high crop yield.


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