Comparative Study of Airborne Pollen from the Northern to the Southern of Tunisia

2019 ◽  
pp. 1-8 ◽  
Author(s):  
S. Hadj Hamda ◽  
A. Ben Dhiab ◽  
M. Msallem ◽  
A. Larbi
Keyword(s):  
Crop Production ◽  
Airborne Pollen ◽  
Flowering Phenology ◽  
Plant Distribution ◽  
The South ◽  
Pollen Type ◽  
The North ◽  
Flowering Season ◽  
Pollen Types ◽  
Study Sites

Aerobiology is a multidisciplinary science dealing with biological particles in the atmosphere generated by natural activities during flowering season. Airborne pollen is now the main studied biological structure which is used as a reliable tool to study plant phenology, plant distribution changes and prediction of crop production. The main aims of this work is to determine the distribution of the different spring flowering species from the North to the South of Tunisia and to establish the pollen spectrum of three regions Mornag (North), Menzel M’hiri (Centre) and Chaal (South) in 2017. Airborne pollen data were collected using three volumetric Hirst-type spore traps placed in Mornag (36°39N; 10°16E), Menzel M’hiri (35°38N; 10°41E) and Chaal (34°34N; 10°19E) during olive flowering season. The highest pollen index was recorded in the north (Mornag, 6487.1) corresponding mainly to 18 different pollen types emitted by anemophilous species with an important presence of Cupressus pollen type having the highest contribution. Lower pollen amounts were recorded in Menzel M’hiri (5983.8) and Chaal (925.3). Olea eurpoeae was the most presented pollen type in these regions. However comparing the different study sites we can note a large distribution of some taxa from north to the south. The main common taxa were Olea europaea, Cupressaceae, Poaceae and Amaranhaceae. Their atmospheric concentrations varied also between the regions. Individual pollen index showed a sharp heterogeneity between the taxa in the same region in one hand and between the study sites in the other hand, thus a statistical analysis was performed to define the main group of taxa according to their individual pollen index. Flowering phenology of the main common taxa was also established.

Seasonal pollen distribution in the atmosphere of Hobart, Tasmania: preliminary observations and congruence with flowering phenology

2010 ◽  
Vol 58 (6) ◽  
pp. 440 ◽  
Author(s):  
D. Y. P. Tng ◽  
F. Hopf ◽  
S. G. Haberle ◽  
D. M. J. S. Bowman
Keyword(s):  
Native Plants ◽  
Airborne Pollen ◽  
Flowering Phenology ◽  
Sampling Location ◽  
Minor Role ◽  
Sampling Effort ◽  
Pollen Load ◽  
Flowering Duration ◽  
Pollen Types ◽  
Atmospheric Pollen

The atmospheric pollen loads of Hobart, Tasmania, Australia, were monitored between September 2007 and July 2009. To examine the match of the airborne pollen composition with the flowering duration of their contributing plants, the phenology of native and non-native plants in various habitats near the pollen-trapping site was undertaken between August 2008 and July 2009. The pollen load was found to have a strong seasonal component associated with the start of spring in September. This is incongruent with the peak flowering season of the total taxa in October. In most taxa, atmospheric pollen signatures appeared before flowering was observed in the field. The presence of most pollen types in the atmosphere also exceeded the observed flowering duration of potential pollen-source taxa. Reasons for this may be related to the sampling effort of phenological monitoring, pollen blown in from earlier flowering populations outside of the sampling area, the ability of pollen to be reworked, and the large pollen production of some wind-pollinated taxa. In 2007–2008, 15 pollen types dominated the atmosphere, accounting for 90% of the airborne pollen load. The top six pollen types belonged to Betula, Cupressaceae, Myrtaceae, Salix, Poaceae and Ulmus. Comparatively, the annual pollen load of Hobart is lower than in most other Australian cities; however, the pollen signal of Betula is inordinately high. Native plants play a minor role as pollen contributors, despite the proximity of native habitats to the pollen-sampling location. The implications of the aerobiological observations are discussed in relation to public health.

scholarly journals Variation of Vitellaria paradoxa phenophases along the north-south gradient in Mali

1970 ◽  
pp. 08-16
Author(s):  
Bokary Allaye Kelly ◽  
Mahesh Poudyal ◽  
Jean-Marc Bouvet
Keyword(s):  
Average Length ◽  
Abiotic Factors ◽  
Permanent Plots ◽  
Future Research ◽  
Vitellaria Paradoxa ◽  
The South ◽  
The North ◽  
Study Sites ◽  
Shea Tree ◽  
Research Challenge

We monitored flowering, fruiting and leafing of Vitellaria paradoxa (shea tree) along the north–south gradient in Mali (West Africa), using three study sites for a period of three years. In each site, adult shea trees were marked and monitored in permanent plots of both field and fallow stands. The chronology of phenophases and their mean length as well as flowering and fruiting were assessed. Our data revealed significant variation according to site and stand. The onset of events starts earlier in the south than in the centre or north, but the period covered by events was almost the same for all sites (3 to 6 months for flowering; 5 to 6 months for fruiting; and 2 to 4 months before full leafing).Flowering and fruiting were more regular in the south, but often as high in the north, with an almost similar trend in both fields and fallows. In the centre, flowering was also high in fields as well as in fallows, while the fruiting was medium to high. We also observed variations in the mean length of phenological events in study sites and stands. Sites in the south showed the highest average length of flowering and leafing (76 days and 44 days, respectively), while the central site showed the greatest length of mean fruiting (110 days).  We observed a significant site*stand interaction and noticeable variation over the years. Our study indicates that phenological events of shea tree could be influenced by several interacting biotic and abiotic factors. A future research challenge in shea phenology would be to discriminate these factors and thus help sustainable management of shea tree parklands.

scholarly journals Growing season precipitation in Finland under recent and projected climate

2010 ◽  
Vol 10 (7) ◽  
pp. 1563-1574 ◽  
Author(s):  
J. S. Ylhäisi ◽  
H. Tietäväinen, ◽  
P. Peltonen-Sainio ◽  
A. Venäläinen ◽  
J. Eklund ◽  
...  
Keyword(s):  
Crop Production ◽  
Early Stage ◽  
Regional Climate ◽  
Growing Season ◽  
Agricultural Crop ◽  
Sampling Errors ◽  
The South ◽  
North East ◽  
The North ◽  
North Eastern

Abstract. The past and projected future precipitation sum in May–September for two areas in Finland, one located in the south-west (SW) and the other in the north-east (NE), is studied using 13 regional climate simulations and three observational datasets. The conditions in the present-day climate for agricultural crop production are far more favourable in the south-western part of the country than the more continental north-eastern Finland. Based on a new high-resolution observational precipitation dataset for Finland (FMI_grid), with a resolution of 10×10 km, the only statistically significant past long-term (1908–2008) precipitation tendencies in the two study regions are positive. Differences between FMI_grid and two other observational datasets during 1961–2000 are rather large in the NE, whereas in the SW the datasets agree better. Observational uncertainties stem from the interpolation and sampling errors. The projected increases in precipitation in the early stage of the growing season would be most favourable for agricultural productivity, but the projected increases in August and September might be harmful. Model projections for the future indicate a statistically significant increase in precipitation for most of the growing season by 2100, but the distribution of precipitation within the growing season is not necessarily the most optimal.

scholarly journals Hybrid data-model-based mapping of soil thickness in a mountainous watershed

2021 ◽  
Author(s):  
Qina Yan ◽  
Haruko Wainwright ◽  
Baptiste Dafflon ◽  
Sebastian Uhlemann ◽  
Carl I. Steefel ◽  
...  
Keyword(s):  
Hybrid Model ◽  
Spatial Resolution ◽  
Soil Layer ◽  
The South ◽  
Soil Thickness ◽  
The North ◽  
Soil Erosion Rate ◽  
East River ◽  
Thickness Prediction ◽  
Study Sites

Abstract. Soil thickness plays a central role in the interactions between vegetation, soils, and topography where it controls the retention and release of water, carbon, nitrogen, and metals. However, mapping soil thickness, here defined as the mobile regolith layer, at high spatial resolution remains challenging. Here, we develop a hybrid model that combines a process-based model and empirical relationships to estimate the spatial heterogeneity of soil thickness with fine spatial resolution (0.5 m). We apply this model to two examples of hillslopes (south-facing and north-facing, respectively) in the East River Watershed in Colorado that validates the effectiveness of the model. Two independent measurement methods – auger and cone penetrometer – are used to sample soil thickness at 78 locations to calibrate the local value of unconstrained parameters within the hybrid model. Sensitivity analysis using the hybrid model reveals that the diffusion coefficient used in hillslope diffusion modelling has the largest sensitivity among all input parameters. In addition, our results from both sampling and modeling show that, in general, the north-facing hillslope has a deeper soil layer than the south-facing hillslope. By comparing the soil thickness estimated between a machine learning approach and this hybrid model, the hybrid model provides higher accuracy and requires less sampling data. Modeling results further reveal that the south-facing hillslope has a slightly faster surface soil erosion rate and soil production rate than the north-facing hillslope, which suggests that the relatively less dense vegetation cover and drier surface soils on the south-facing slopes may influence soil characteristics. With only seven parameters for calibration, this hybrid model can provide a realistic soil thickness map at other study sites by with a relatively small amount of sampling dataset. Integrating process-based modeling and statistical analysis not only provides a thorough understanding of the fundamental mechanisms for soil thickness prediction, but integrates the strengths of both statistical approaches and process-based modeling approaches.

scholarly journals A Survey of Atmospheric Pollen and Spores in North-Western Nigeria

2018 ◽  
Vol 10 (2) ◽  
pp. 182-192
Author(s):  
Olugbenga Shadrak ALEBIOSU ◽  
Olusola H. ADEKANMBI
Keyword(s):  
Meteorological Parameters ◽  
Airborne Pollen ◽  
Health Concern ◽  
Pollen Types ◽  
Pollen Concentrations ◽  
Atmospheric Pollen ◽  
Local Plants ◽  
Study Sites ◽  
The Impact ◽  
North Western

The incidence of airborne pollen occurring as aeroallergens of varied levels at different periods of the year has generated some public health concern globally. The present study was conducted in order to examine the monthly depositional rate of airborne pollen and fern spores, as well as the impact of meteorological parameters and local plants on pollen distribution at two study sites in Kaduna and Sokoto States of North Western Nigeria. The study spanned a period of one year, during which a modified Tauber pollen sampler was employed in the collection of atmospheric pollen and fern spores; local plants were also enumerated. Residual solution was collected monthly, subjected to acetolysis and the treated residues were viewed for microscopic studies. The results reveal monthly distribution of airborne pollen and fern spore types at the study sites during the sampling period. Dominant pollen types in Kaduna State were those of Alchornea laxiflora, Pinus caribaea, Terminalia sp., Sapotaceae and Poaceae family. Pollen of Syzygium guineense, Alchornea sp., Sapotaceae and Poaceae dominated in Sokoto State. Spores of Pteris sp., Nephrolepis sp. and a trilete fern were also recovered at both locations. Some local plants in the immediate vegetation contributed to the aeroflora of these locations. No significant correlation was recorded between monthly total pollen concentrations and mean monthly meteorological parameters of the locations. It is imperative to investigate the allergenicity of these dominant pollen types, so as to aid pollen hypersensitive individuals in adopting appropriate prophylactic measures.

scholarly journals Infection Levels of the Microsporidium Larssoniella duplicati in Populations of the Invasive Bark Beetle Ips duplicatus: From Native to New Outbreak Areas

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 131 ◽  
Author(s):  
Soňa Zimová ◽  
Karolina Resnerová ◽  
Hana Vanická ◽  
Jakub Horák ◽  
Jiří Trombik ◽  
...  
Keyword(s):  
Picea Abies ◽  
Bark Beetle ◽  
The South ◽  
Infection Level ◽  
The North ◽  
Ips Duplicatus ◽  
Specific Pathogen ◽  
Outbreak Areas ◽  
Study Sites ◽  
A Site

The microsporidium Larssoniella duplicati (Weiser, Holuša, Žižka, 2006) is a specific pathogen of the bark beetle Ips duplicatus (C.R. Sahlberg, 1836), which is a serious pest of Norway spruce (Picea abies (L.) H. Karst) in Europe. From 2011 to 2016, infection levels of L. duplicati and other pathogens in I. duplicatus populations were assessed along a gradient, ranging from areas in the north, where the beetle is native, to areas in the south, where the beetle has only recently invaded. The 21 study sites ranged in altitude from 229 to 1009 m a.s.l. We found that pathogen infection levels in I. duplicatus populations decreased from the native areas in the north to the new areas of beetle expansion in the south. We also found that pathogen level increased with altitude. The L. duplicati infection levels were not associated with the infection levels of other beetle natural enemies. The infection level decreased with the length of time of beetle establishment in an area. The infection level increased with the number of beetles trapped and dissected at a site.

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

US and Russian policies and strategies in the Middle East: Iraq and Syria as a model

2019 ◽  
pp. 220
Author(s):  
Esraa Aladdin Noori ◽  
Nasser Zain AlAbidine Ahmed
Keyword(s):  
Middle East ◽  
East Asia ◽  
Balance Of Power ◽  
Western World ◽  
International Conflicts ◽  
The South ◽  
The West ◽  
The North ◽  
East Region ◽  
Middle East Region

The Russian-American relations have undergone many stages of conflict and competition over cooperation that have left their mark on the international balance of power in the Middle East. The Iraqi and Syrian crises are a detailed development in the Middle East region. The Middle East region has allowed some regional and international conflicts to intensify, with the expansion of the geopolitical circle, which, if applied strategically to the Middle East region, covers the area between Afghanistan and East Asia, From the north to the Maghreb to the west and to the Sudan and the Greater Sahara to the south, its strategic importance will seem clear. It is the main lifeline of the Western world.

Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin

2020 ◽  
Author(s):  
A., C. Prasetyo
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Mineral Content ◽  
Hydrocarbon Generation ◽  
Well Test ◽  
Burial History ◽  
The South ◽  
North West ◽  
The North ◽  
Geological Processes

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.

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