scholarly journals Vegetation establishment improves topsoil properties and enzyme activities in the dry Aral Sea Bed, Kazakhstan

Forestist ◽  
2018 ◽  
Vol 68 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Jiae An ◽  
Seongjun Kim ◽  
Hanna Chang ◽  
Asia Khamzina ◽  
Yowhan Son
Keyword(s):  
Enzyme Activities ◽  
Aral Sea ◽  
Sea Bed ◽  
Vegetation Establishment

scholarly journals Changes in basic soil properties and enzyme activities along an afforestation series on the dry Aral Sea Bed, Kazakhstan

2019 ◽  
Vol 16 (1) ◽  
pp. 26-31
Author(s):  
Jiae An ◽  
Hanna Chang ◽  
Seung Hyun Han ◽  
Asia Khamzina ◽  
Yowhan Son
Keyword(s):  
Soil Properties ◽  
Enzyme Activities ◽  
Aral Sea ◽  
Sea Bed

scholarly journals Isotopic Signatures as an Indicator of Long-Term Water-Use Efficiency of Haloxylon Plantations on the Dried Aral Sea Bed

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 99
Author(s):  
Asia Khamzina ◽  
Jiae An ◽  
Hanna Chang ◽  
Yowhan Son
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Aral Sea ◽  
Water Withdrawal ◽  
Composition Analysis ◽  
Isotopic Signatures ◽  
Sandy Substrate ◽  
Sea Bed ◽  
Use Efficiency

The desiccation of the Aral Sea due to water withdrawal from contributing rivers has resulted in an unprecedented change in the region’s climate, from maritime to hot dry desert. Afforestation has been implemented on the desiccated seafloor—the Aralkum Desert—for stabilizing the exposed substrate. However, studies on the long-term status of the afforested sites are limited. Here, we examined C and N isotopic signatures in Haloxylon aphyllum plantations, as indicators of time-integrated plant response to the prevalent water and salinity constraints, in northern Aralkum, Kazakhstan. Foliar 13C composition analysis in a chronosequence of H. aphyllum plantation sites (aged 1–27 years) on the sandy substrate revealed a significant trend towards higher water-use efficiency in older plantations, possibly in response to declining water availability. A lack of correlation between plant 13C signature and soil electrical conductivity suggests no history of salt stress despite the saline environment. Furthermore, 15N enrichment in plant tissue in the water-limited Aralkum ecosystem indicates the relative openness of N cycling. There was an increase in species richness and self-propagation at the plot scale, indicating successful afforestation effort. Coupled with other approaches, isotope discrimination might elucidate mechanisms underlying stress tolerance in H. aphyllum, which could support the afforestation efforts.

scholarly journals Historical reconstruction of the Aral Sea shrinking by a full 3-D wetting and drying model ECOSMO

2008 ◽  
Vol 1 (1) ◽  
pp. 243-283 ◽  
Author(s):  
I. Alekseeva ◽  
C. Schrum
Keyword(s):  
Sea Ice ◽  
Surface Area ◽  
Aral Sea ◽  
Salt Flux ◽  
Scale Model ◽  
Time Step ◽  
Ice Dynamics ◽  
Wetting And Drying ◽  
Sea Bed ◽  
Ice Model

Abstract. Several decades ago, the Aral Sea was the fourth out of the biggest lakes all over the world. Due to intense irrigation in the Aral Sea basin an imbalance in the water budget occurred and caused dramatic shrinking of the Aral Sea. With the present paper a sea-ice model for the Aral Sea has been developed, aiming in resolving the long-term development of the sea including drastic volume and surface area changes. The necessary requirement for such a model is a mass conservative wetting and drying scheme which has been developed in the application. By performing sensitivity experiments on different implementations of wetting and drying schemes, a significant influence of waggling on the volume and salt budget was identified for a hindcast under realistic forcing and the need for a volume and mass conserving scheme was demonstrated. Using a mass conserving implementation a model hindcast was performed for 1979–1993 by using the ECMWF re-analysis (ERA-15) meteorological data and modeled evaporation. Consideration of surface area changes in a temporal resolution of the model time step allowed for a realistic description of non-linear interactions between volume loss and evaporation changes. The sea-ice model was able to successfully simulate sea level and sea surface area decrease as well as sea-ice dynamics on a multiyear to decadal time scale. Model predicted evaporation was found to result in significantly improved volume budgets for the Aral Sea and in realistic predictions of the Aral Sea shrinking. Furthermore, by comparing the simulated average salinities to observed ones, it could be shown that the present model concept neglecting additional salt flux effects such as salt precipitation and salinity deposition on the dried sea bed, is adequate to reproduce observed mean salinities during the period of investigation.

scholarly journals Ice-Gouging Topography of the Exposed Aral Sea Bed

2019 ◽  
Vol 11 (2) ◽  
pp. 113 ◽  
Author(s):  
Stepan Maznev ◽  
Stanislav Ogorodov ◽  
Alisa Baranskaya ◽  
Aleksey Vergun ◽  
Vasiliy Arkhipov ◽  
...  
Keyword(s):  
Aral Sea ◽  
Motion Processing ◽  
Remotely Sensed Data ◽  
Large Lakes ◽  
Side Scan Sonar ◽  
Sea Bottom ◽  
Sea Bed ◽  
Aerial Vehicle ◽  
Remote Sensing Techniques

Ice gouging, or scouring, i.e., ice impact on the seabed, is a well-studied phenomenon in high-latitude seas. In the mid-latitudes, it remains one of the major geomorphic processes in freezing seas and large lakes. Research efforts concerning its patterns, drivers and intensity are scarce, and include aerial and geophysical studies of ice scours in the Northern Caspian Sea. This study aims to explain the origin of the recently discovered linear landforms on the exposed former Aral Sea bottom using remotely sensed data. We suggest that they are relict ice gouges, analogous to the modern ice scours of the Northern Caspian, Kara and other seas and lakes, previously studied by side scan sonar (SSS) surveys. Their average dimensions, from 3 to 90 m in width and from hundreds to thousands of meters in length, and spatial distribution were derived from satellite imagery interpretation and structure from motion-processing of UAV (unmanned aerial vehicle) images. Ice scouring features are virtually omnipresent at certain seabed sections, evidencing high ice gouging intensity in mid-latitude climates. Their greatest density is observed in the central part of the former East Aral Sea. The majority of contemporary ice gouges appeared during the rapid Aral Sea level fall between 1980 and the mid-1990s. Since then, the lake has almost completely drained, providing a unique opportunity for direct studies of exposed ice gouges using both in situ and remote-sensing techniques. These data could add to our current understanding of the scales and drivers of ice impact on the bottom of shallow seas and lakes.

Identifying potential vegetation establishment areas on the dried Aral Sea floor using satellite images

2020 ◽  
Vol 31 (18) ◽  
pp. 2749-2762 ◽  
Author(s):  
Jiwon Kim ◽  
Cholho Song ◽  
Sujong Lee ◽  
Hyun‐Woo Jo ◽  
Eunbeen Park ◽  
...  
Keyword(s):  
Satellite Images ◽  
Aral Sea ◽  
Sea Floor ◽  
Potential Vegetation ◽  
Vegetation Establishment

High time resolution enzyme cytochemistry of rod outer segment

1990 ◽  
Vol 48 (3) ◽  
pp. 878-879
Author(s):  
Takuma Saito ◽  
Toshihiro Takizawa
Keyword(s):  
Enzyme Activities ◽  
Outer Segment ◽  
Rapid Change ◽  
High Time Resolution ◽  
Visual Cell ◽  
Enzyme Cytochemistry ◽  
Activation Effect ◽  
Rod Outer Segment ◽  
Enzymatic Cascades ◽  
Rapid Drop

Cells and tissues live on a number of dynamic metabolic pathways, which are made up of sequential enzymatic cascades.Recent biochemical and physiological studies of vision research showed the importance of cGMP metabolism in the rod outer segment of visual cell, indicat ing that the photon activated rhodopsin exerts activation effect on the GTP binding protein, transducin, and this act ivated transducin further activates phosphodiesterase (PDEase) to result in a rapid drop in cGMP concentration in the cytoplasm of rod outer segment. This rapid drop of cGMP concentration exerts to close the ion channel on the plasma membrane and to stop of inward current brings hyperpolarization and evokes an action potential.These sequential change of enzyme activities, known as cGMP cascade, proceeds quite rapidly within msec order. Such a rapid change of enzyme activities, such as PDEase in rod outer segment, was not a matter of conventional histochemical invest igations.

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