scholarly journals SALINITY: A MAJOR ENVIRONMENTAL FACTOR IN THE SUSTAINABILITY OF THE BLUE ECONOMY

Author(s):  
Indrani Dhar

The inshore region of the Bay of Bengal is one of the less-studied regions of the world ocean in terms of sustainability of Blue Economy while being one of the most exploited bodies of water to benefit a considerable chunk of the Indian population. For the first time, thirty-six years of in situ data at two locations in the northwestern Bay preferably in the lower Gangetic delta region has been analyzed to identify long-term trends in salinity. The salinity values obtained for Jharkhali and Haldia, situated in the lower Gangetic delta region exhibit extreme contrasting profiles. Jharkhali shows an increasing trend, whereas Haldia shows a pronounced decreasing trend of salinity with the passage of time. The results point towards the vulnerability of Jharkhali station towards corrosion of engineering structures, which might exert a negative impact on the sustainability of Blue Economy in this region.

Climate ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 111
Author(s):  
Kwesi Akumenyi Quagraine ◽  
Francis Nkrumah ◽  
Cornelia Klein ◽  
Nana Ama Browne Klutse ◽  
Kwesi Twentwewa Quagraine

Focusing on West Africa, a region riddled with in situ data scarcity, we evaluate the summer monsoon monthly rainfall characteristics of five global reanalysis datasets: ERA5, ERA-Interim, JRA-55, MERRA2, and NCEP-R2. Their performance in reproducing the West African monsoon (WAM) climatology, interannual variability, and long-term trends for the main monsoon months are compared to gauge-only and satellite products. We further examine their ability to reproduce teleconnections between sea surface temperatures and monsoon rainfall. All reanalyses are able to represent the average rainfall patterns and seasonal cycle; however, regional biases can be marked. ERA5, ERA-Interim, and NCEP-R2 underestimate rainfall over areas of peak rainfall, with ERA5 showing the strongest underestimation, particularly over the Guinea Highlands. The meridional northward extent of the monsoon rainband is well captured by JRA-55 and MERRA2 but is too narrow in ERA-Interim, for which rainfall stays close to the Guinea Coast. Differences in rainband displacement become particularly evident when comparing strong El Niño Southern Oscillation (ENSO) years, where all reanalyses except ERA-Interim reproduce wetter Sahelian conditions for La Niña, while overestimating dry conditions at the coast except for NCEP-R2. Precipitation trends are not coherent across reanalyses and magnitudes are generally overestimated compared to observations, with only JRA-55 and NCEP-R2 displaying the expected positive trend in the Sahel. ERA5 generally outperforms ERA-Interim, highlighting clear improvements over its predecessor. Ultimately, we find the strengths of reanalyses to strongly vary across the region.


2000 ◽  
Vol 18 (6) ◽  
pp. 653-665 ◽  
Author(s):  
A. V. Mikhailov ◽  
D. Marin

Abstract. Further development of the method proposed by Danilov and Mikhailov is presented. The method is applied to reveal the foF2 long-term trends on 30 Northern Hemisphere ionosonde stations. Most of them show significant foF2 trends. A pronounced dependence of trend magnitude on geomagnetic (invariant) latitude is confirmed. Periods of negative/positive foF2 trends corresponding to the periods of long-term increasing/decreasing geomagnetic activity are revealed for the first time. Pronounced diurnal variations of the foF2 trend magnitude are found. Strong positive foF2 trends in the post-midnight-early-morning LT sector and strong negative trends during daytime hours are found on the sub-auroral stations for the period with increasing geomagnetic activity. On the contrary middle and lower latitude stations demonstrate negative trends in the early-morning LT sector and small negative or positive trends during daytime hours for the same period. All the morphological features revealed of the foF2 trends may be explained in the framework of contemporary F2-region storm mechanisms. This newly proposed F2-layer geomagnetic storm concept casts serious doubts on the hypothesis relating the F2-layer parameter long-term trends to the thermosphere cooling due to the greenhouse effect.Key words: Ionosphere (ionosphere-atmosphere interactions; ionospheric disturbances)


Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Sarah Stanley

An air-sampling study has captured long-term trends in the concentrations of five key atmospheric gases for the first time.


2021 ◽  
Vol 12 ◽  
Author(s):  
Lise Verbruggen ◽  
Lindsay Sprimont ◽  
Eduard Bentea ◽  
Pauline Janssen ◽  
Azzedine Gharib ◽  
...  

Despite ample evidence for the therapeutic potential of inhibition of the cystine/glutamate antiporter system xc− in neurological disorders and in cancer, none of the proposed inhibitors is selective. In this context, a lot of research has been performed using the EMA- and FDA-approved drug sulfasalazine (SAS). Even though this molecule is already on the market for decades as an anti-inflammatory drug, serious side effects due to its use have been reported. Whereas for the treatment of the main indications, SAS needs to be cleaved in the intestine into the anti-inflammatory compound mesalazine, it needs to reach the systemic circulation in its intact form to allow inhibition of system xc−. The higher plasma levels of intact SAS (or its metabolites) might induce adverse effects, independent of its action on system xc−. Some of these effects have however been attributed to system xc− inhibition, calling into question the safety of targeting system xc−. In this study we chronically treated system xc− - deficient mice and their wildtype littermates with two different doses of SAS (160 mg/kg twice daily or 320 mg/kg once daily, i.p.) and studied some of the adverse effects that were previously reported. SAS had a negative impact on the survival rate, the body weight, the thermoregulation and/or stress reaction of mice of both genotypes, and thus independent of its inhibitory action on system xc−. While SAS decreased the total distance travelled in the open-field test the first time the mice encountered the test, it did not influence this parameter on the long-term and it did not induce other behavioral changes such as anxiety- or depressive-like behavior. Finally, no major histological abnormalities were observed in the spinal cord. To conclude, we were unable to identify any undesirable system xc−-dependent effect of chronic administration of SAS.


Author(s):  
S. P. Goloborodko ◽  
O. M. Dymov

Relevance of the research. If greenhouse gases in the XXI century enter the atmosphere in the same volume as now, the increase in the average temperature on the planet will reach 2–4°C, and therefore the threat of extinction of up to 20–30% of species of animals and plants in existing biocenosis is not excluded. At the same time, the water level in the world ocean will rise, which during the XX century became higher by 17 cm, that is, more than for the previous 2000 years. Simultaneously with the increase in the average monthly air temperature in the conditions of natural moisturizing (without irrigation) of the southern Steppe subzone of Ukraine in recent years, insufficient precipitation has been recorded, especially in July, August and September that, according to various estimates, is typical for the semi-desert and desert. As a result, the aridity of the climate has increased and the frequency of droughts has risen as well. If for the period of 400 years, in the XI–XIV centuries droughts occurred only 8 times, in the XVII–XVIII – 17, in the XIX – 20, in the XX century the number of them increased to 30. The purpose of the article is to reveal the causes of global climate change on the planet and its impact on agricultural production of the southern Steppe subzone that resulted in increasing the coefficient of moisture, evaporation and moisture deficit. Research methods. The study was carried out using long-term meteorological observations of Kherson meteorological station. Scientific research was based on the complex application of statistical, monographic, abstract-logical methods and system analysis. Research results. The analysis of the main causes of global and regional climate change was conducted. Four models of the bases of climate change on the planet Earth were made. The influence of climate change on the formation of crops yield in the subzone of the southern Steppe was specified. The amount of precipitation fell during the growing period of 2011–2017 in medium dry and dry years shows that, compared to the long-term average precipitation, it was significantly lower and amounted to 47.2–63.6 mm. In average for the 65 years (1945–2010) evaporation was 722.0 mm, and the deficit of moisture, respectively 487.4 mm. In wet years, the volatility does not exceed 608.6 mm, and the deficit of moisture was made up of 243.6 mm. In average as to water supply years the evaporation increased up to 645.7–746.3 mm and the deficit of moisture increased up to 406.7–507.7 mm. In mid-dry and dry years, evaporation increased up to 769.8–934.5 mm, and the deficit of moisture – up to 580.9–791.0 mm. Conclusions. The decrease in precipitation, especially in dry years, compared to average annual indicators, was recorded in spring period as 24–27% and in autumn – as 62–65%, along with a simultaneous increase in air temperature in those periods as 2.7 and 2.8°C respectively. In general, during the vegetation period the increase in evaporation was 30–31% and the deficit of moisture was 53–55% that resulted in low yields of crops. The main way to overcome the negative impact of global climate change on the agricultural production of the southern Steppe subzone is the effective use and further extending the areas of actual irrigation, that will ensure stable high yields and food security of the state.


2020 ◽  
Vol 78 (2) ◽  
pp. 69-78
Author(s):  
Aldijana Mušović ◽  
Rifat Škrijelj ◽  
Mahir Gajević ◽  
Belma Kalamujić Stroil ◽  
Adi Vesnić ◽  
...  

AbstractBuško Blato Reservoir, the third largest hydro accumulation in Europe, is situated in the south-eastern part of the karstic Livanjsko Polje Valley. This aquatic ecosystem is distinguished by a very rich ichthyofauna and the presence of four endemic fish species. Numerous studies focus on ichthyological researches of Buško Blato Reservoir. Its ichthyofauna has been exposed to changes in ecological factors, which in turn reflected on the structure and composition of fish populations. The main objective of this paper was to assess the current state and predict future trends in the ichthyofauna structure and dynamics based on the field data and comprehensive analyses of literature data. The results of the research indicated the presence of 11 fish species from four families, which is the largest number of fish species ever recorded in this ecosystem. Sander lucioperca, Lepomis gibbosus, Pseudorasbora parva and Tinca tinca were recorded for the first time in this ecosystem, while some previously recorded species were not found. The results of the analyses clearly indicate the presence of natural interspecific competition and significant level of threats to the endemic fish species caused by human activities.


2020 ◽  
Vol 12 (16) ◽  
pp. 2522 ◽  
Author(s):  
Matthew L. Hammond ◽  
Stephanie A. Henson ◽  
Nicolas Lamquin ◽  
Sébastien Clerc ◽  
Craig Donlon

The Sentinel-3 tandem project represents the first time that two ocean colour satellites have been flown in the same orbit with minimal temporal separation (~30 s), thus allowing them to have virtually identical views of the ocean. This offers an opportunity for understanding how differences in individual sensor uncertainty can affect conclusions drawn from the data. Here, we specifically focus on trend estimation. Observational chlorophyll-a uncertainty is assessed from the Sentinel-3A Ocean and Land Colour Imager (OLCI-A) and Sentinel-3B OLCI (OLCI-B) sensors using a bootstrapping approach. Realistic trends are then imposed on a synthetic chlorophyll-a time series to understand how sensor uncertainty could affect potential long-term trends in Sentinel-3 OLCI data. We find that OLCI-A and OLCI-B both show very similar trends, with the OLCI-B trend estimates tending to have a slightly wider distribution, although not statistically different from the OLCI-A distribution. The spatial pattern of trend estimates is also assessed, showing that the probability distributions of trend estimates in OLCI-A and OLCI-B are most similar in open ocean regions, and least similar in coastal regions and at high northern latitudes. This analysis shows that the two sensors should provide consistent trends between the two satellites, provided future ageing is well quantified and mitigated. The Sentinel-3 programme offers a strong baseline for estimating long-term chlorophyll-a trends by offering a series of satellites (starting with Sentinel-3A and Sentinel-3B) that use the same sensor design, reducing potential issues with cross-calibration between sensors. This analysis contributes an important understanding of the reliability of the two current Sentinel-3 OLCI sensors for future studies of climate change driven chlorophyll-a trends.


Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 71
Author(s):  
Vasily Bogoyavlensky ◽  
Igor Bogoyavlensky ◽  
Roman Nikonov ◽  
Tatiana Kargina ◽  
Evgeny Chuvilin ◽  
...  

This article describes the results of an Arctic expedition studying the new giant gas blowout crater in the north of Western Siberia, in the central part of the Yamal Peninsula in 2020. It was named C17 in the geoinformation system “Arctic and the World Ocean” created by the Oil and Gas Research Institute of the Russian Academy of Sciences (OGRI RAS). On the basis of remote sensing, it can be seen that the formation of the crater C17 was preceded by a long-term growth of the perennial heaving mound (PHM) on the surface of the third marine terrace. Based on the interpretation of satellite images, it was substantiated that the crater C17 was formed in the period 15 May–9 June 2020. For the first time, as a result of aerial photography from inside the crater with a UAV, a 3D model of the crater and a giant cavity in the ground ice, formed during its thawing from below, was built. The accumulation of gas, the pressure rise and the development of gas-dynamic processes in the cavity led to the growth of the PHM, and the explosion and formation of the crater.


2003 ◽  
Vol 21 (3) ◽  
pp. 751-760 ◽  
Author(s):  
A. V. Mikhailov ◽  
B. A. de la Morena

Abstract. A relationship between foE trends and geomagnetic activity long-term variations has been revealed for the first time. By analogy with earlier obtained results on the foF2 trends it is possible to speak about the geomagnetic control of the foE long-term trends as well. Periods of increasing geomagnetic activity correspond to negative foE trends, while these trends are positive for the decreasing phase of geomagnetic activity. This "natural" relationship breaks down around 1970 (on some stations later) when pronounced positive foE trends have appeared on most of the stations considered. The dependence of foE trends on geomagnetic activity can be related with nitric oxide variations at the E-layer heights. The positive foE trends that appeared after the "break down" effect may also be explained by the [NO] decrease which is not related to geomagnetic activity variations. But negative trends or irregular foE variations on some stations for the same time period require some different mechanism. Chemical pollution of the lower thermosphere due to the anthropogenic activity may be responsible for such abnormal foE behavior after the end of the 1960s.Key words. Ionosphere (ionosphere-atmosphere interactions; ionospheric disturbances)


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