Temat: Population Dynamics - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Von Bertalanffys growth dynamics with strong Allee effect
Autorzy:: Rocha, J.
Aleixo, Sandra
Powiązania:: https://bibliotekanauki.pl/articles/729888.pdf
Data publikacji:: 2012
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:: Von Bertalanffy's model
population dynamics
Allee effect
Opis:: Von Bertalanffy's model is one of the most popular differential equation used in order to study the increase in average length or weight of fish. However, this model does not include demographic Allee effect. This phenomenon is known in the fisheries literature as "depensation", which arises when populations decline rapidly at low densities. In this paper we develop and investigate new corrected von Bertalanffy's models with Allee effects. The generalization that we propose results from considering correction factors, one of rational type and the others of polynomial type, where two parameters are considered. The use of a parameter C > 0 leads the presented generalization, which yields some more flexible models with variable extinction rates. An Allee limit or unstable equilibrium $E^u$ is incorporated so that the models under study have strong Allee effect. We analyze and show the transition from the strong Allee effect to the inexistence of this effect, through by a "weakening" of the Allee effect, depending on the parameters C and $E^u$. Finally, we discuss the flexibility of corrected von Bertalanffy's sigmoid growth curves. So, the correspondents inflexion points are variable, i.e., the fish mass when the growth rate is maximum may be varied.
Źródło:: Discussiones Mathematicae Probability and Statistics; 2012, 32, 1-2; 35-45
1509-9423
Pojawia się w:: Discussiones Mathematicae Probability and Statistics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Badania nad liczebnością wyspowej populacji nornicy rudej (Clethrionomys glareolus, Schreber 1780) i ich znaczenie dla teorii
The population dynamics of bank voles (Clethrionomys glareolus, Schreber 1780) and its significance for theory
Autorzy:: Bujalska, Gabriela
Powiązania:: https://bibliotekanauki.pl/articles/1817871.pdf
Data publikacji:: 2003-12-31
Wydawca:: Uniwersytet Kardynała Stefana Wyszyńskiego w Warszawie
Tematy:: Clethrionomys glareolus
nornica ruda
liczebność populacji
population dynamics
Opis:: This is an overview of long-term studies (1966-1997) on the bank vole - Clethrionomys glareolus (Photo 1). population inhabiting Crabapple Island in NE Poland. The history of recognition of causes affecting population dynamics as well as variable interpretation of the facts comprising the theory of functional relations in that population is described. Meandering ideas can be illustrated by Fig. 1. The population dynamics (each year data on population numbers in April, July, and October are shown) is presented in Fig. 2. The evidence is provided that the population exhibits a weak 3.8 year and a much more clear 9.4-year cycle (Fig. 3). The number of sexually mature females, that is those able to reproduce, has been relatively stable and independent of the population size or of the immature female numbers (Fig. 4). The reason is the territoriality of mature females: the female territory (part of the female home range) cannot be visited by other mature females. A tendency toward territoriality was also noted among mature males, which numbers were limited by the availability of mature females, and therefore also relatively stable. Such a social system can be considered gynocentric.
Źródło:: Studia Ecologiae et Bioethicae; 2003, 1, 1; 429-444
1733-1218
Pojawia się w:: Studia Ecologiae et Bioethicae
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Field and Laboratory Studies of the Earthworm Dendrobaena Alpina
Autorzy:: Kostecka, J.
Butt, K. R.
Powiązania:: https://bibliotekanauki.pl/articles/124743.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:: earthworms
Dendrobaena alpina
field study
laboratory culture
population dynamics
Opis:: Distribution of Dendrobaena alpina covers the mountainous region of central Europe, where it has a high dominance and frequency index. This work describes data from field studies conducted over two annual cycles in the Bieszczady National Park (BNP), Poland, in different types of beech forest. Densities of this species ranged from 47–231 g·m ^-2 with associated biomasses of 19–90 g·m ^-2. Most (66%) were recovered from less than 0.1 m soil depth with a further 28% from up to 0.2 m. Further, the animals were collected alive from Lutowiska, close to the BNP to obtain baseline data on the life history of D. alpina. Mature individuals were kept in isolation and cocoon production monitored on a 2 monthly basis. Immature individuals were kept until they reached maturity, when they were paired, with combined output of cocoons regularly monitored. Cocoons were collected, had their masses determined and were incubated. Hatchability was recorded, as was estimated duration of incubation and growth to maturity. Field-collected adults had a mean mass of 1.4 g and at 15 ºC, these produced an average of 1.83 cocoons·worm ^-1·month ^-1. Zero cocoons were produced by further specimens, collected as immature, grown to maturity and maintained in isolation. Recently-matured, paired D. alpina produced an average of 1.65 cocoons·worm ^-1·month ^-3. Cocoons had a mean mass of 19 mg. At 15 ºC, cocoons produced by recently matured adults hatched after 80 days (82% viable), but after 2 months the majority of cocoons failed to hatch. Hatchling growth from an average of 18 mg to maturity required 7–11 months in the given substrate.
Źródło:: Journal of Ecological Engineering; 2015, 16, 5; 213-217
2299-8993
Pojawia się w:: Journal of Ecological Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Changes in the aquatic moss Sphagnum denticulatum Brid. population abundance in a softwater lake over a period of three years
Autorzy:: Szmeja, J
Powiązania:: https://bibliotekanauki.pl/articles/57078.pdf
Data publikacji:: 2010
Wydawca:: Polskie Towarzystwo Botaniczne
Tematy:: aquatic moss
population dynamics
Sphagnum denticulatum
population abundance
soft water lake
lake
phenology
Opis:: Changes in population abundance of submerged Sphagnum denticulatum Brid. were studied in an acidic and oligotrophic lake in NW Poland over three years. Individuals were counted in a moss carpet at a depth of 2.5 m on 4 experimental plots, 1 × 1 m each, every 30 days for 36 months using the SCUBA method. PAR intensity was seasonally variable (in winter higher than in summer). Changes in water pH, conductivity, HCO3- concentration, hydration and sediment pH were statistically insignificant (p > 0.05). In the summer of the second study year the moss carpet disappeared almost completely due to a massive bloom of filamentous green algae. Periods of growth, regression and regeneration were observed in the population. The stabilisation of population size took 24 months and followed the pattern: slight fluctuations, then rapid growth and repetition of slight fluctuations. The first stage lasted nine, the second four and the third nine months. These stages took place irrespective of seasons, temperature or PAR intensity. Each rapid increase in abundance lasted about 30 days, at PAR intensity >20% and water temperature ranging from 11 to 16oC (in winter, spring or autumn). The regression stage brought about by the algal bloom started in the second year (in summer) and lasted six months (until the end of January in the third year). The population regeneration began in winter (in February, water temperature 3.0oC, PAR about 20%, ice cover 0.15 m) and finished with the end of spring. The population of S. denticulatum shows a repetitive pattern of abundance variations, which is seriously disturbed in summer, especially after a warm spring, by a massive bloom of filamentous green algae.
Źródło:: Acta Societatis Botanicorum Poloniae; 2010, 79, 2; 167-173
0001-6977
2083-9480
Pojawia się w:: Acta Societatis Botanicorum Poloniae
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Dynamics of a two sex population with gestation period
Autorzy:: Busoni, Giorgio
Palczewski, Andrzej
Powiązania:: https://bibliotekanauki.pl/articles/1208215.pdf
Data publikacji:: 2000
Wydawca:: Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:: differential equations with delay
stationary solutions
population dynamics
mathematical modelling
Opis:: We investigate a mathematical model of population dynamics for a population of two sexes (male and female) in which new individuals are conceived in a process of mating between individuals of opposed sexes and their appearance is postponed by a period of gestation. The model is a system of two partial differential equations with delay which are additionally coupled by mathematically complicated boundary conditions. We show that this model has a global solution. We also analyze stationary ('permanent') solutions and show that such solutions exist if the model parameters satisfy two nonlinear relations.
Źródło:: Applicationes Mathematicae; 2000, 27, 1; 21-34
1233-7234
Pojawia się w:: Applicationes Mathematicae
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Labor force dynamics and economic performance: A case of Nigeria, India, and China
Autorzy:: Omolola Oyedepo, Elizabeth
Powiązania:: https://bibliotekanauki.pl/articles/32443882.pdf
Data publikacji:: 2024
Wydawca:: Uniwersytet Ekonomiczny w Katowicach
Tematy:: labor force
economic performance
demographic change
population dynamics
ARDL model
Opis:: Aim/purpose – This study investigated the nexus between labor force dynamics and economic performance in Nigeria, India, and China. Design/methodology/approach – The study used annual time series data spanning from 1991 to 2021 obtained from World Development Indicators (WDI). After the unit root stationarity test, the Autoregressive Distributed Lag Model (ARDL) was used for the analysis. Findings – Findings from the study support a positive short-run relationship between labor force participation and economic growth in all three countries. However, in China, population growth impacts the economy positively in the long run, while life expectancy at birth negatively impacts the economy in the short run. This is because China’s population is aging. In India, employment in the industrial and service sectors positively impacts the economy in the long run. In the short run, life expectancy at birth influences the economy negatively. Furthermore, in Nigeria, the industrial and service sector employment impact the economy negatively in the long run, though there are positive effects in the short run. Research implications – The Indian government needs policy reforms in the areas of education and health to take advantage of the potential of its youthful population. The Nigerian government requires implementing a wide range of education, investment, and employment-generating policies to foster tangible economic growth. These reforms could help both India and Nigeria take advantage of the potential for demographic change. The Chinese government, already having policy reforms in place, is geared towards improved fertility and population growth for economic growth in the near future. These policies, coupled with the study’s findings, could provide a more comprehensive understanding of the implications of demographic change on economic performance. Originality/value contribution – This analysis explored and compared the demographic potentials of two young countries (India and Nigeria) and an aging, wealthy economy (China) from the working class. Policy lessons for the attainment of demographic dividends are borrowed from China.
Źródło:: Journal of Economics and Management; 2024, 46; 143-170
1732-1948
Pojawia się w:: Journal of Economics and Management
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Storage of hydrogenous gas in geological formations: self-organisation methane gas
Autorzy:: Toleukhanov, A.
Kaltayev, A.
Panfilov, M.
Powiązania:: https://bibliotekanauki.pl/articles/298661.pdf
Data publikacji:: 2013
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:: porous media
hydrogen
reactive transport
bacteria
neuston
chemotaxis
population dynamics
oscillations
Opis:: In the case of producing large amounts of hydrogenous gas, currently there are no problems related to basic techniques of hydrogen production and distribution, but the main technological problem will consists of storing it in order to regulate the difference between permanent or increasing gas production and seasonally modulated gas consumption. The most efficient and most inexpensive method of storing large amounts of hydrogen is to inject them in geological formations like aquifers, depleted gas reservoirs, or salt caverns (Zittel and Wurster 1996). The cost is of order $ 3.5 per 1 GJ (Taylor et al. 1986). Several underground storages of hydrogen (USH) or town gas exist in the word, as for instance, Teeside in the UK, in Texas, in Russia, Kiel in Germany, Lobodice in Czechoslovakia, Beynes - an ex-storage in France. During several tens of years the storage of hydrogen was considered as something deja-vu, to be similar to that of natural gas, which is amplified by the chemical inactivity of hydrogen and its very low solvability in groundwater [Bulatov 1979; Carden and Paterson 1979; Lindblom 1985; Paterson 1983]. Nevertheless, quite unusual behaviour of UHS was discovered by in situ monitoring of the gas composition extracted during the cycle "production" which followed the cycle "injection". These observations (Smigai et al. 1990; Buzek et al. 1994) revealed high variations of gas composition in time and space. In particular, a significant reduction in the H2 and CO2 contents and a simultaneous increase in CH4 contents were observed in the Lobodice town gas storage facility (Smigai et al. 1990). Similar phenomena were recorded in Beynes. After several months of injection and storage, at the beginning of the cycle "production" the twofold increase of the methane contents in the reservoir gas and the twofold reduction of the CO2 CO contents was observed. The contents of hydrogen decreased by 1.4. The explanation to these observations has been done in (Buzek et al. 1994) in terms of the in situ methane generators by methanogenic bacteria which catalyse the reaction between hydrogen and CO2/CO, by producing methane and water. Further observations have revealed even more unusual effects within the storage facility, such as creating a spatial alternation of the areas saturated preferably by hydrogen or methane. This proved an in situ natural separation of chemical components in space. Thus, we are dealing with a natural reactor which partially destroys CO2 and H2 and doubles the mass of methane. It is clear that the problem is important for industry as it concerns both the energy sector and ecology. The resulting economical efficiency of such a process can be estimated only after the physical and mathematical modeling of all possible scenarios of the reservoir behaviour. The development of such a model represents the main objective of this paper.
Źródło:: AGH Drilling, Oil, Gas; 2013, 30, 1; 241-245
2299-4157
2300-7052
Pojawia się w:: AGH Drilling, Oil, Gas
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The dynamics of the population of a steppe perennial Senecio macrophyllus M.BIEB. during xerothermic grassland overgrowing
Autorzy:: Czarnecka, B
Powiązania:: https://bibliotekanauki.pl/articles/56894.pdf
Data publikacji:: 2009
Wydawca:: Polskie Towarzystwo Botaniczne
Tematy:: population dynamics
steppe plant
Senecio macrophyllus
xerothermic grassland
life-stage structure
Opis:: The study aimed to determine the long-term changes of the Senecio macrophyllus M.BIEB. population traits: the abundance, reproduction mode, individual fecundity, seed rain and recruitment of new genets in the course of xerothermic grassland overgrowing. The study had also the applied goal: to estimate the chances of "special care" species to survive in the changing environment without management regime for the maintenance of grassland. The model object was the island population of large-leaved ragwort on Biała Góra (the White Mountain) near Tomaszów Lubelski, South-East Poland. To achieve these aims I used the following sets of data: phytosociological relev,s made in plant communities in an interval of 16-18 years; repeated elaboration of the numbers and life-stage structure of the population, both by non-surface and surface method; observation of plants, life cycle in 50 labelled genets; population reproduction and seed rain amounts. The area of an open xerothermic grassland decreased due to the process of overgrowing by bushes which was accompanied by the increasing coverage of forest and meadow herbs as well as monocotyledons, mainly Brachypodium pinnatum and Calamagrostis epigejos. The abundance of the S. macrophyllus population noticable diminished. The flowering mode has been changing during years from an oscillation to a chaotic type which caused the significant decreasing of the individual fecundity, population reproduction and seed rain. In last years it was reflected in the interruption of juveniles’ recruitment.
Źródło:: Acta Societatis Botanicorum Poloniae; 2009, 78, 3; 247-256
0001-6977
2083-9480
Pojawia się w:: Acta Societatis Botanicorum Poloniae
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Bark beetles in the Tatra Mountains. International research 1998-2005 - an overview
Autorzy:: Grodzki, W.
Turcani, M.
Jakus, R.
Hlasny, T.
Rasi, R.
McManus, M.L.
Powiązania:: https://bibliotekanauki.pl/articles/38438.pdf
Data publikacji:: 2010
Wydawca:: Instytut Badawczy Leśnictwa
Tematy:: bark beetle
beetle
Tatras Mountains
Picea abies
population dynamics
Polska
Slovakia
Opis:: This paper is a review of fundamental information on bark beetles and their interactions with several predisposing factors (air pollution, drought/temperature interactions, windthrows, management activities) that are thought to contribute to the outbreaks in the High Tatra Mountains. The findings of many research projects indicate that the impact of air pollution on bark beetle populations is indirect and complex and that the disturbances in the physiology and natural resistance of trees may be of crucial importance to bark beetle population dynamics. An active forest protection approach is needed to be applied to the secondary Norway spruce forests affected in the past by human activity. Bark beetle populations in natural and near-natural forests (mainly in the upper montane zone) are regulated by natural mechanisms; bark beetles are therefore a natural factor contributing to forest development, including the transition of future generations of spruce.
Źródło:: Folia Forestalia Polonica. Series A . Forestry; 2010, 52, 2
0071-6677
Pojawia się w:: Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Global existence and asymptotic behavior for a nonlinear degenerate SIS model
Autorzy:: Ziane, T. A.
Powiązania:: https://bibliotekanauki.pl/articles/952842.pdf
Data publikacji:: 2013
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:: reaction diffusion systems
degenerate diffusion
global existence
asymptotic behavior
population dynamics
Opis:: In this paper we investigate the global existence and asymptotic behavior of a reaction diffusion system with degenerate diffusion arising in the modeling and the spatial spread of an epidemic disease.
Źródło:: Opuscula Mathematica; 2013, 33, 4; 615-630
1232-9274
2300-6919
Pojawia się w:: Opuscula Mathematica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Solvability and Asymptotic Behavior of a Population Problem Taking into Account Random Mating and Females Pregnancy
Autorzy:: Skakauskas, V.
Powiązania:: https://bibliotekanauki.pl/articles/929725.pdf
Data publikacji:: 2000
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:: dynamika populacji
migracja
population dynamics
random mating
gestation of females
migration
Opis:: Two deterministic age-sex-structured population dynamics models are discussed taking into account random mating of sexes (without formation of permanent male-female couples), possible destruction of the fetus (abortion), and female's pregnancy. One of them deals with both random and directed diffusion in the whole space while in the other the population is assumed to be nondispersing. The population consists of three components: one maleand two female, the latter two being the single (nonfertilized) female and the fertilized one. The case of a separable solution of the limited nondispersing population (in which death moduli can be decomposed into the sum of two terms where one of them depends on time and age and theother is a function of time and the population size) is analyzed. The existence of a unique solution of the Cauchy problem for the nondispersing population model is proved and its longtime behavior is demonstrated. An analogous situation for the dispersing population is analyzed, too.
Źródło:: International Journal of Applied Mathematics and Computer Science; 2000, 10, 1; 37-61
1641-876X
2083-8492
Pojawia się w:: International Journal of Applied Mathematics and Computer Science
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Population changes and characteristics of demographic processes in Tbilisi
Zmiany liczby ludności i charakter procesów demograficznych w Tbilisi
Autorzy:: Meladze, Giorgi
Loladze, Nika
Powiązania:: https://bibliotekanauki.pl/articles/691729.pdf
Data publikacji:: 2017
Wydawca:: Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:: płodność
migracje
prognoza
dynamika liczby ludności
fertility
migration
Tbilisi
prognosis
population dynamics
Opis:: Na początku lat 90. XX wieku w Gruzji miało miejsce natychmiastowe zakończenie wieloletnich stosunków gospodarczych ze Związkiem Radzieckim. Dodatkowo konflikty zbrojne w Abchazji i Osetii Północnej doprowadziły do kryzysu społeczno-gospodarczego i politycznego w Gruzji. Wszystkie te wydarzenia miały ogromny wpływ na procesy demograficzne w Tbilisi. Niniejszy artykuł ma na celu ukazanie głównych czynników społeczno-ekonomicznych i kulturowych dotyczących zmian demograficznych i procesów demograficznych w postsowieckiej Tbilisi. Dodatkowo autorzy przedstawili prognozy zmian liczby ludności w latach 2015–2030.
At the beginning of the 1990s, as a result of the dissolution of the Soviet Union, an instant termination of economic relations that had existed for dozens of years took place in Georgia. Along with the armed conflicts in the regions of Tskhinvali and Abkhazia it has led to a full-fledged socio-economic and political crisis in Georgia. These unordinary events have had a great influence on the demographic processes at hand in Tbilisi. This article aims to establish the effects of the main socio-economic and cultural factors on population change and demographic processes in post-Soviet Tbilisi and offers prognosis on population change according to low, medium and high estimates for 2015–2030.
Źródło:: Space – Society – Economy; 2017, 19; 87-103
1733-3180
2451-3547
Pojawia się w:: Space – Society – Economy
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: The population dynamics of aphids Cinara juniperi De Geer on the shrubs of Juniperus communis L. in urban conditions of Lublin
Dynamika populacji mszyc Cinara juniperi De Geer na krzewach Juniperus communis L. w warunkach miejskich Lublina
Autorzy:: Jaśkiewicz, B.
Kot, I.
Powiązania:: https://bibliotekanauki.pl/articles/11541670.pdf
Data publikacji:: 2007
Wydawca:: Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:: population dynamics
shrub
urban condition
Juniperus communis
Cinara juniperi
Lublin city
aphid
Opis:: Studies on the population dynamics of aphids Cinara juniperi De Geer on the shrubs of Juniperus communis L. in the urban conditions of Lublin were conducted in the years 2002–2004 in two types of sites: a street one and a park one. The first individuals of this species were most frequently observed at the turn of April and May, while the maximum population was found in the first half of May. The course of the weather conditions affected the population dynamics of aphids. Those insects were observed in much bigger numbers on the shrubs growing in the street site. The preying of C. juniperi caused browning and drying out of the needles and inhibition of the stem growth, which had an influence on lower decorative character of the examined plants.
Badania nad dynamiką populacji mszyc Cinara juniperi De Geer na krzewach Juniperus communis L. w warunkach miejskich Lublina prowadzono w latach 2002–2004 na dwóch typach stanowisk: przyulicznym i parkowym. Pierwsze osobniki tego gatunku najczęściej notowano na przełomie kwietnia i maja, a maksimum populacji w pierwszej połowie maja. Na dynamikę populacji mszyc miał wpływ przebieg warunków pogodowych. Owady te znacznie liczniej obserwowano na krzewach rosnących na stanowisku przyulicznym. Żerowanie miodownicy jałowcowej powodowało brązowienie i usychanie igieł oraz zahamowanie wzrostu pędów, co miało wpływ na obniżenie dekoracyjności badanych roślin.
Źródło:: Acta Scientiarum Polonorum. Hortorum Cultus; 2007, 06, 4; 3-10
1644-0692
Pojawia się w:: Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Spirostomum teres: A Long Term Study of an Anoxic-Hypolimnion Population Feeding upon Photosynthesizing Microorganisms
Autorzy:: Macek, Miroslav
Sánchez Medina, Ximena
Picazo, Antonio
Peštová, Dana
Bautista Reyes, Fernando
Montiel Hernández, Jorge Ricardo
Alcocer, Javier
Merino Ibarra, Martín
Camacho, Antonio
Powiązania:: https://bibliotekanauki.pl/articles/52089923.pdf
Data publikacji:: 2020
Wydawca:: Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:: Spirostomum teres
ciliate
population dynamics
maar lake
anoxic hypolimnion
picocyanobacteria
feeding rate
Opis:: The pelagic / anoxic hypolimnion population of Spirostomum teres was investigated as a part of the long-term ciliates’ monitoring (2003–2016) in an oligo- to mesotrophic monomictic hyposaline crater lake Alchichica (Puebla / Veracruz, Mexico), including an analysis of picoplankton (both heterotrophic, HPP and autotrophic, APP) and inorganic compounds of nitrogen (ammonium, nitrite, nitrate), phosphorus (dissolved reactive phosphorus, DRP) and silicon. Additionally, detailed studies of the ciliate vertical distribution and feeding activity measured upon fluorescently labelled APP (picocyanobacteria) were carried out. The results were compared with those from a neighbour freshwater crater lake La Preciosa and with a meromictic karstic lake La Cruz (Cuenca, Spain). The ciliate vertical distribution within the water column was very well defined: During the first decade, the benthic population was frequently found throughout a developing stratification of the lake. The established stratification of the lake turned the conditions favourable for the formation of an oxycline / hypolimnion population, typically, several meters below the deep chlorophyll maximum (formed basically by diatoms); the population preferred the layers without detectable dissolved oxygen. However, an observed gradient of light (PAR) could support both oxygenic and anoxygenic photosynthesis. Late stratification after deepening of the thermocline reduced the layers with S. teres population to a minimum apparently due to the drastic change in physicochemical conditions within a metalimnion, coupled with an oxycline, and limited to 1 to 2 meters; microstratification was found. Last years, the very bottom population disappeared or it was reduced and the late stratification S. teres peaks were smaller or did not appeared. Generally, S. teres oxycline / anoxic hypolimnion population was observed from June through November. Optimum picoplankton numbers in conditions that supported the ciliate growth were found: The ciliate was peaking at APP of 0.6 to 1 × 10⁵ cells mL^–1; the optimum of HPP was observed round 1.4 × 10⁶ cells mL^–1. S. teres was efficiently feeding upon picocyanobacteria in numbers of 10⁵ cells mL^–1 reaching the clearance rate of 2000 nL cell^–1h^–1, which represented in average 130 to 210 cells cell^–1h^–1 ingested. Feeding upon purple sulphur bacteria was observed but only during the end of the lake stable stratification when the ciliate population was already dropping. On the other hand, the volume specific clearance of S. teres upon picocyanobacteria (10³ h^–1) did not support the hypothesis that they could serve as a sole prey. Feeding upon eukaryote phytoplankton (chlorophytes Monoraphidium minutum, diatoms Cyclotella choc tawhatcheeana) could be of higher importance that previously supposed. Additionally, a use of ingested and retained photosynthetic prokaryotes is hypothesized.
Źródło:: Acta Protozoologica; 2020, 59, 1; 13-38
0065-1583
1689-0027
Pojawia się w:: Acta Protozoologica
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Parameterisation of a population model for Acartia spp. in the Southern Baltic Sea. Part 1. Development time
Autorzy:: Dzierzbicka-Glowacka, L.
Lemieszek, A.
Zmijewska, M.I.
Powiązania:: https://bibliotekanauki.pl/articles/49034.pdf
Data publikacji:: 2009
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: population dynamics
environment condition
Baltic Sea
development
Acartia bifilosa
Acartia
growth
Gdansk Gulf
population model
Opis:: The copepod model (see Dzierzbicka-Głowacka 2005b),red uced to a zero-dimensional population model (Fennel 2001,S tegert et al. 2007),i s calibrated for Acartia spp. under the environmental conditions typical of the southern Baltic Sea. Most of the coefficients used in the model are taken from the literature,co ntaining values from various published studies and parameters derived for similar species. The parameters for growth are presented in Part 1; those for population dynamics are given in Part 2. Ingestion rates,whic h are dependent on developmental stage, food supply,temp erature and weight of the animals, are estimated for Acartia bifilosa at 15◦C from the Gdańsk Deep after the experimental data of Ciszewski & Witek (1977). In Part 1 the model presents the change in mean individual mass in successive stages. Quantitative formulae are obtained describing the effects of temperature and food concentration on the development time of Acartia spp. for each of the model stage groups. The generation time during the seasons in the upper layer of the Gdańsk Deep is also determined. The simulations computed here are similar to the experimental results. Part 2 (Dzierzbicka-Głowacka et al. 2009 – this issue) will evaluate egg production as a function of the above-mentioned parameters,temp erature and food availability.
Źródło:: Oceanologia; 2009, 51, 2; 165-184
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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