scholarly journals Multiyear changes of the Danube delta marine edge

2019 ◽  
Vol 46 (5) ◽  
pp. 474-484
Author(s):  
M. V. Mikhailova ◽  
V. I. Kravtsova ◽  
V. N. Morozov
Keyword(s):  
Water Flow ◽  
Sediment Load ◽  
External Factors ◽  
Danube Delta ◽  
Channel Network ◽  
River Deltas ◽  
Delta Formation ◽  
Comparison Of The Results ◽  
The Impact

With the help of field and remote (space) methods, detailed studies of long-term changes of the Danube delta coastline (DCL) were carried out. It was established that the DCL displacements (progradation or retreat) can be an effective indicator of delta formation process as a whole: the dynamics of the delta channel network and the redistribution of water flow and sediment load between the branches, the impact of external factors on the delta (river water flow and sediment load, wind and wave action, rise or drop of the sea level). To determine the causes and characteristics of the Danube DCL changes on seven genetically homogeneous areas the contribution of various factors to the balance of sand sediments forming the DCL was evaluated. Locations of the DCL progradation or retreat were determined. Comparison of the results of a study of the Danube DCL dynamics with the data on changes of morphology and regime of other large deltas may allow one to assess the causes and trends of modern processes in river deltas.

scholarly journals Impact of sediment–seawater cation exchange on Himalayan chemical weathering fluxes

2016 ◽  
Vol 4 (3) ◽  
pp. 675-684 ◽  
Author(s):  
Maarten Lupker ◽  
Christian France-Lanord ◽  
Bruno Lartiges
Keyword(s):  
Cation Exchange ◽  
Chemical Weathering ◽  
Sediment Load ◽  
Relative Proportion ◽  
River System ◽  
Exchange Capacity ◽  
Sediment Flux ◽  
Continental Scale ◽  
The Impact

Abstract. Continental-scale chemical weathering budgets are commonly assessed based on the flux of dissolved elements carried by large rivers to the oceans. However, the interaction between sediments and seawater in estuaries can lead to additional cation exchange fluxes that have been very poorly constrained so far. We constrained the magnitude of cation exchange fluxes from the Ganga–Brahmaputra river system based on cation exchange capacity (CEC) measurements of riverine sediments. CEC values of sediments are variable throughout the river water column as a result of hydrological sorting of minerals with depth that control grain sizes and surface area. The average CEC of the integrated sediment load of the Ganga–Brahmaputra is estimated ca. 6.5 meq 100 g−1. The cationic charge of sediments in the river is dominated by bivalent ions Ca2+ (76 %) and Mg2+ (16 %) followed by monovalent K+ (6 %) and Na+ (2 %), and the relative proportion of these ions is constant among all samples and both rivers. Assuming a total exchange of exchangeable Ca2+ for marine Na+ yields a maximal additional Ca2+ flux of 28  ×  109 mol yr−1 of calcium to the ocean, which represents an increase of ca. 6 % of the actual river dissolved Ca2+ flux. In the more likely event that only a fraction of the adsorbed riverine Ca2+ is exchanged, not only for marine Na+ but also Mg2+ and K+, estuarine cation exchange for the Ganga–Brahmaputra is responsible for an additional Ca2+ flux of 23  ×  109 mol yr−1, while ca. 27  ×  109 mol yr−1 of Na+, 8  ×  109 mol yr−1 of Mg2+ and 4  ×  109 mol yr−1 of K+ are re-absorbed in the estuaries. This represents an additional riverine Ca2+ flux to the ocean of 5 % compared to the measured dissolved flux. About 15 % of the dissolved Na+ flux, 8 % of the dissolved K+ flux and 4 % of the Mg2+ are reabsorbed by the sediments in the estuaries. The impact of estuarine sediment–seawater cation exchange appears to be limited when evaluated in the context of the long-term carbon cycle and its main effect is the sequestration of a significant fraction of the riverine Na flux to the oceans. The limited exchange fluxes of the Ganga–Brahmaputra relate to the lower than average CEC of its sediment load that do not counterbalance the high sediment flux to the oceans. This can be attributed to the nature of Himalayan river sediment such as low proportion of clays and organic matter.

Preliminary Assessment of the Impact of Draining of Iraqi Marshes on Kuwait's Northern Marine Environment. Part I. Physical Manipulation

1999 ◽  
Vol 40 (7) ◽  
pp. 75-87 ◽  
Author(s):  
Abdul Nabi Al-Ghadban ◽  
T. Saeed ◽  
A. M. Al-Dousari ◽  
H. Al-Shemmari ◽  
M. Al-Mutairi
Keyword(s):  
Marine Environment ◽  
Negative Impact ◽  
Arabian Gulf ◽  
Preliminary Assessment ◽  
Sediment Distribution ◽  
Comparison Of The Results ◽  
The Impact ◽  
Water Depths ◽  
Physical Manipulation

Kuwait's northern marine area is considered to be the receiving basin for the influx of sediments and associated pollutants from the Shatt Al-Arab estuary. In recent years, Iraq has undertaken to drain the southern marshes, which acted as a sink for the sediment and its associated pollutants. The draining process is expected to significantly increase the rate of sedimentation and change the hydrodynamic regime of the northern Arabian Gulf. Thirty-three bottom sediment samples from the area likely to be impacted by the draining of the marshes were collected and studied in 1997-98. Locations of sampling stations were selected as close to an earlier study done in 1982. The recent marine sediments of the study area are subdivided into five textural classes: sandy clay, clay, silt, mud and sandy mud. The comparison of the results of this study with those of the 1982 study showed that finer sediments were deposited. Based on sediment distribution, characteristics of bottom sediments and the topographic nature of the study area, a north-south sediment transport from Shatt Al-Arab and the southern part of Iraq, affecting the marine environment of Kuwait, is inferred. Comparison of water depths of the 1956 and 1986 hydrographic maps, revealed that more deposition occurred in the northern area, and this was attributed to the draining process. In general, there were some indications of the negative impact of the draining of the marshes, however, long-term and more detailed studies are needed.

Long-term changes of four macrobenthic assemblages from 1978 to 1992

1997 ◽  
Vol 77 (2) ◽  
pp. 287-310 ◽  
Author(s):  
J.M. Fromentin ◽  
F. Ibanez ◽  
J.C. Dauvin ◽  
J.M. Dewarumez ◽  
B. Elkaim
Keyword(s):  
Fine Sand ◽  
Temporal Variations ◽  
Local Conditions ◽  
North West ◽  
The North ◽  
Macrobenthic Assemblages ◽  
Climatic Event ◽  
Comparison Of The Results ◽  
The Impact

Changes in four macrobenthic assemblages of the muddy-fine sand Abra alba community along the north-west French coast were compared using several numerical analyses (distogram, Eigen vector filtering, clustering and multi-dimensional scaling). The faunistic composition of these four assemblages continuously changed during the 1978–1992 period. These modifications are characterized by more or less rapid and abrupt successions of distinct groups of species, but the amplitude and the frequency of these changes are different between sites. Comparison of the results provided by different analyses also reveal that these four macrobenthic assemblages did not fluctuate in parallel, and that local conditions might play a key role on their temporal variations. However, it is shown that a major mesoscale climatic event, the alternation of mild and cold periods, probably also influenced the temporal variations of these four macrobenthic assemblages. Thus it is likely that there is a combination of both local and mesoscale events influencing these communities. In certain cases, changes in local conditions were the major source of variations. Sometimes the impact of the mesoscale conditions was more apparent, especially at the northern sites where the amplitude of the variations of temperature was greater.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

Examining the Impact of the Disabled Youth Peer Development Initiative: What are the Long-Term Outcomes?

2003 ◽  
Author(s):  
Teresa Garate-Serafini ◽  
Jose Mendez ◽  
Patty Arriaga ◽  
Larry Labiak ◽  
Carol Reynolds
Keyword(s):  
Long Term Outcomes ◽  
The Disabled ◽  
The Impact

The Impact of Different Treatments on Long-Term Symptoms in Vestibular Schwannoma

2014 ◽  
Vol 75 (S 02) ◽  
Author(s):  
Morten Lund-Johansen ◽  
Øystein Tveiten ◽  
Monica Finnkirk ◽  
Erling Myrseth ◽  
Frederik Goplen ◽  
...  
Keyword(s):  
Vestibular Schwannoma ◽  
The Impact

The influence of inflation targeting on the pass-through effect of the exchange rate

2018 ◽  
pp. 70-84
Author(s):  
Ph. S. Kartaev ◽  
Yu. I. Yakimova
Keyword(s):  
Developing Countries ◽  
Monetary Policy ◽  
Exchange Rate ◽  
Inflation Targeting ◽  
Policy Regime ◽  
Short And Long Term ◽  
The Exchange Rate ◽  
Pass Through ◽  
The Impact

The paper studies the impact of the transition to the inflation targeting regime on the magnitude of the pass-through effect of the exchange rate to prices. We analyze cross-country panel data on developed and developing countries. It is shown that the transition to this regime of monetary policy contributes to a significant reduction in both the short- and long-term pass-through effects. This decline is stronger in developing countries. We identify the main channels that ensure the influence of the monetary policy regime on the pass-through effect, and examine their performance. In addition, we analyze the data of time series for Russia. It was concluded that even there the transition to inflation targeting led to a decrease in the dependence of the level of inflation on fluctuations in the ruble exchange rate.

Secular stagnation in the modern world

2018 ◽  
pp. 125-141 ◽  
Author(s):  
S. M. Drobyshevsky ◽  
P. V. Trunin ◽  
A. V. Bozhechkova
Keyword(s):  
Public Debt ◽  
Capital Accumulation ◽  
Technological Development ◽  
Japanese Economy ◽  
Modern World ◽  
Key Factors ◽  
Destruction Process ◽  
Secular Stagnation ◽  
The Impact

The paper studies the factors of secular stagnation. Key factors of long-term slowdown in economic growth include the slowdown of technological development, aging population, human capital accumulation limits, high public debt, creative destruction process violation etc. The authors analyze key theoretical aspects of long-term stagnation and study the impact of these factors on Japanies economy. The authors conclude that most of the factors have significant influence on the Japanese economy for recent decades, but they cannot explain all dynamics. For Russia, on the contrary, we do not see any grounds for considering the decline in the economy since 2013 as an episode of secular stagnation.

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