Wyniki wyszukiwania - AGRO

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Spatial variability of low-flows in the upper Warta River catchment

100%

Kozek M.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2018

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tom 17

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nr 3

Low-flows are an important component of the river regime. Their identification advances our knowledge about the formation of water resources in drought conditions. The analyses that we have carried out aimed to indicate the spatial structure of these flows. Our study area was the Warta River catchment up to the water-gauge at Sieradz. The input research material consisted of a sequence of daily discharge data for 12 gauging stations located in this catchment, in the period of 1971-2000, made available by IMGW-PIB. At the first stage, periodic flows based on flow time-duration curve and annual minimum flows were determined. Their values have been converted into specific flows, which facilitated the conduct of comparative analyses. On the basis of the obtained results, the spatial variability of low-flows in studied catchment was evaluated. The annual number of days with low-flows was identified for all gauge sections. The dynamics and distribution of low flow appearing in the multiannual period were evaluated. The analyses we have carried out made it possible to identify the factors, which determine the structure of low-flows. Research results have been illustrated with relevant maps and graphs.

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Spatial variability of soil moisture in grassland

88%

Janik G.

International Agrophysics

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2005

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tom 19

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nr 1

3

Spatial variability in the activity of hydrolytic enzymes in a marine beach [Southern Baltic Sea]

88%

Mudryk Z. J., Podgorska B.

Polish Journal of Ecology

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2005

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tom 53

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nr 2

Potential activity of hydrolytic microbial extracellular enzymes were determined in a sandy beach in Sopot, (Southern Baltic Sea) in July 2001. Among of the five monitored enzymes, the highest level of activity (314.28 nM MCA g⁻¹d.w. h⁻¹) was determined in the aminopeptidase whereas chitinase had the lowest level (0.50 nM MUF g⁻¹d.w. h⁻¹) of potential activity. Usually, the ranking of the activity rates of the assayed enzymes was following: aminopeptidase > lipase > β-glucosidase > α-glucosidase > chitinase. Clear gradients in the level of enzymatic activity were determined in horizontal profile of the beach. The maximum activity of studied enzymes was recorded in sand collected under seawater and at the waterline.

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Temporal pattern prevails over spatial variability in phytoplankton communities from a subtropical water supply reservoir

75%

Lv H., Yang J., Liu L.

Oceanological and Hydrobiological Studies

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2013

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tom 42

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nr 4

5

Mapping of soil conditions in precision agriculture

75%

Lukas V., Neudert L., Kren J.

Acta Agrophysica

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2009

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tom 13

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nr 2[167]

6

Hydrogeochemistry and magnitude of SGD in the Bay of Puck, Southern Baltic Sea

75%

Klostowska Z., Szymczycha B., Lengier M., Zarzeczanska D., Dzierzbicka-Glowacka L.

Oceanologia

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2020

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tom 62

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nr 1

7

Spatial and temporal variability of soil water content

75%

Oyedele D. J., Tijani F. O.

International Agrophysics

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2010

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tom 24

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nr 2

171-176

8

Acid volatile sulphide estimation using spatial sediment covariates in the Eastern Upper Gulf of Thailand: multiple geostatistical approaches

75%

Chaikaew P., Sompongchaiyakul P.

Oceanologia

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2018

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tom 60

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nr 4

9

Spatial and temporal variability of sea surface temperature in the Baltic Sea based on 32-years (1982–2013) of satellite data

75%

Stramska M., Bialogrodzka J.

Oceanologia

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2015

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tom 57

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nr 3

10

Temporal stability of electrical conductivity in a sandy soil

75%

Pedrera-Parrilla A., Brevik E. C., Giraldez J. V., Vanderlinden K.

International Agrophysics

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2016

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tom 30

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nr 3

11

Spatial distribution of topsoil water content along a loess hillslope transect

75%

Usowicz B., Rejman J.

Acta Agrophysica

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2000

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tom 35

The paper presents statistical, geostatistical and fractal analysis of variability of topsoil water pontent along a loess hillslope. Spatial dependence of topsoil water content was observed on studied sites. On a site with plants, the range of spatial dependence was smaller than on a site without plants. Fractal dimension showed that topsoil water on a site with plants was more randomized than on a site without, il.

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Spatial variability of recent sedimentation rates in the Eastern Gotland Basin (Baltic Sea)

75%

Hille S., Leipe T., Seifert T.

Oceanologia

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2006

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tom 48

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nr 2

In order to study recent sedimentation rates in the Eastern Gotland Basin, 52 short sediment cores collected from the deepest part (<150 m)of the Basin in 2003 were investigated. The upper parts of all the cores were distinctly laminated and dark in colour, followed by a homogeneous, greyish lower part. The thickness of the laminated sequences varied from 17 to 300 mm. 210Pb dating analyses of selected cores revealed that the change from non-laminated to laminated sediments happened about 100 years ago, indicating a shift from predominantly oxic bottom water conditions to anoxic conditions. Used as a time marker, this shift in the sediment texture enabled sediment accumulation rates to be estimated for all sediment cores. The observed mean linear sedimentation rate for the whole basin was 0.93 ± 0.67 mm yr−1. The respective bulk sediment accumulation rates ranged from 10.5 to 527 g m−2 yr−1 with an average of 129 ± 112 g m−2 yr−1, indicating a high spatial variability of sedimentation rates within the basin. This agrees very well with the long-term sedimentation pattern since the Litorina transgression. The observed pattern clearly reflects the hydrographic conditions at the seafloor as studied by modelled near-bottom current velocities.

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Statistical treatment of spatial variability in field trials

75%

Golaszewski J.

Natural Sciences

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2000

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tom 05

14

Observed variability in physical and biogeochemical parameters in the Central Arabian Gulf

63%

Rakib F., Al-Ansari E. M. A. S., Husrevoglu Y. S., Yigiterhan O., Al-Maslamani I., Aboobacker V. M., Vethamony P.

Oceanologia

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2021

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tom 63

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nr 2

15

Can the studies at a spatial scale of 100s meters detect the spatio-temporal fluctuations of a parasite assemblage?

63%

Parietti M., Merlo M. J., Etchegoin J. A.

Acta Parasitologica

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2013

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tom 58

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nr 4

The importance of small-scale heterogeneity in local factors which overrides that of larger-scales factors, suggest that local factors play a major role in determining the richness and prevalence of larval digeneans in intertidal gastropods. The restricted distribution of the snail Heleobia australis along a 500 m transect in Cangrejo creek (Mar Chiquita, Argentina) provides a good opportunity to test the assumption that a study at spatial scale of 100s meters can detect spatiotemporal fluctuations of a larval digenean assemblage. To analyze that, 3600 specimens of H. australis were collected seasonally during the year 2011. A quantitative variation and a space-time interaction between sampling points and seasons of the year for the total prevalence of larval digeneans and snail’s densities were found, as well as a positive correlation with abiotic factors. These results revealed that the fluctuations in the community of larval digeneans of the snail H. australis can be detected at small spatial scale, using its natural distribution of 500 m. This study also highlights the importance of seasonality as a factor that must be considered in studies focused on the search for patterns structuring the communities of larval digeneans, at medium and large scales.

16

The impact of a non-uniform land surface on the radiation environment over an Arctic fjord – a study with a 3D radiative transfer model for stratus clouds over the Hornsund fjord, Spitsbergen

63%

Rozwadowska A., Gorecka I.

Oceanologia

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2012

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tom 54

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nr 4

17

The impact of tides and waves on near-surface suspended sediment concentrations in the English Channel

63%

Guillou N., Rivier A., Chapalain G., Gohin F.

Oceanologia

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2017

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tom 59

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nr 1

Numerous ecological problems of continental shelf ecosystems require a refined knowledge of the evolution of suspended sediment concentrations (SSC). The present investigation focuses on the spatial and temporal variabilities of near-surface SSC in coastal waters of the English Channel (western Europe) by exploiting numerical predictions from the Regional Ocean Modeling System ROMS. Extending previous investigations of ROMS performances in the Channel, this analysis refines, with increased spatial and temporal resolutions, the characterization of near-surface SSC patterns revealing areas where concentrations are highly correlated with evolutions of tides and waves. Significant tidal modulations of near-surface concentrations are thus found in the eastern English Channel and the French Dover Strait while a pronounced influence of waves is exhibited in the Channel Islands Gulf. Coastal waters present furthermore strong SSC temporal variations, particularly noticeable during storm events of autumn and winter, with maximum near-surface concentrations exceeding 40 mg l1 and increase by a factor from 10 to 18 in comparison with time-averaged concentrations. This temporal variability strongly depends on the granulometric distribution of suspended sediments characterized by local bimodal contributions of silts and sands off coastal irregularities of the Isle of Wight, the Cotentin Peninsula and the southern Dover Strait.

18

The variability of selected features of Gladiolus imbricatus L. in relation to successive stages of meadow communities following the mowing cessation

63%

Kostrakiewicz-Gieralt K.

Polish Journal of Ecology

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2014

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tom 62

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nr 2

Molinietum caeruleae meadows belong to the most endangered plant communities in Central Europe, nowadays suffering due to the lack of management. The land abandonment promotes strong secondary expansion of macroforbs, sedges or willows, contributing to decrease of the species diversity. In light of these findings very interesting seems to be the evaluation of the variability of features of populations of rare meadow species. In Poland one of strictly protected plant is Gladiolus imbricatus L. It is a tuberous, clonal plant with sword-like leaves and tall stalks bearing purple flowers collected in one-sided inflorescence. The studies of spatio-temporal variability of selected features of subpopoulations of Gladiolus imbricatus were carried out in the years 2009-2011 in Kraków-Kostrze (Southern Poland) in patches of Molinietum caeruleae with different species composition. In Patch I chiefly occurred small meadow species, Patch II was prevailed by shrub willow, Patch III was dominated by tall-growing macroforbs, Patch IV was characterized by substantial share of large-tussock grasses, while Patch V was overgrown by tall rhizomatous grass Phragmites communis. The plant canopy height and ground moisture raised from Patch I, via Patches II, III and IV, to Patch V. Moreover, in all sites the above mentioned parameters increased moderately in consecutive seasons. The decline of abundance of subpopulations observed in the consecutive years and in the successive patches might be caused by a mortality of individuals, a physical damage of tubers, as well as a prolonged dormancy of genets. The structure of developmental stages were similar in consecutive years but differed significantly among Patches. The increasing trend toward senility noted in successive sites could be an effect of lack of microsites suitable for seedling recruitment or absence of vegetative regeneration. The dimensions of leaf blades, flowering stalks and inflorescences remained similar in the subsequent seasons, but they augmented significantly in the successive patches. The length and the width of capsules did not change significantly between seasons and sites. Concluding, it might be assumed, that the perspectives for survivability of subpopulations diminish gradually from Patch I, via Patches II, III and IV to Patch V. Simultaneously, it should be pointed out that prospects for persistence in each place steadily decrease in effect of continuous deterioration of site conditions.

19

Variability of fluorescence of dissolved and suspended substances of biological origin in the Gdansk Basin during the International Ecological Experiment “Sopot 87”

63%

Karabashev G. S., Khanaev S. A., Petrosov A. Y.

Oceanologia

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1990

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tom 28

20

Ocena zmienności przestrzennej uziarnienia gleby i zawartości węgla organicznego w krajobrazie lessowym

63%

Rejman J., Iglik I., Brodowski R., Turski M., Smarz M.

Acta Agrophysica

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2011

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tom 18

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nr 2[193]

Zmienność przestrzenną zawartości frakcji piasku, pyłu i iłu oraz C organicznego gleby badano w obrębie pola położonego w wierzchowinowej części krajobrazu lessowego. Parametry gleby oznaczono w warstwie ornej (0-25 cm), a próby pobrano w układzie siatki regularnej 10×10 m (72 punkty). Stwierdzono, że zmienność przestrzenna badanych cech gleby dobrze opisywana była izotropowymi modelami semiwariancji typu sferycznego. Zasięg zmienności przestrzennej poszczególnych frakcji uziarnienia był uzależniony od wielkości cząstek, będąc najmniejszym dla zawartości iłu (28,4 m), a największym dla piasku (121,8 m). Wartość najmniejsza oznacza, że przyjęty krok próbkowania był wystarczający do oceny zmienności przestrzennej frakcji uziarnienia w wierzchowinowej części zlewni lessowej. Zmienność przestrzenną zawartości C organicznego charakteryzował izotropowy model sferyczny o zasięgu autokorelacji 50,2 m.

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