Jaroslav Vrba
YOU?
Author Swipe
View article: Response of aquatic invertebrate communities to different management strategies in central European fishponds
Response of aquatic invertebrate communities to different management strategies in central European fishponds Open
Fishponds are essential ecosystems, inhabited by many different groups of biota and having commercial and non-commercial functions. Therefore, managing fishponds can be a crucial parameter affecting all biota inhabiting a given fishpond, a…
View article: Restrictions on Regularized Fisher and Dilatonic Spacetimes Implied by High-Frequency Quasiperiodic Oscillations Observed in Microquasars and Active Galactic Nuclei
Restrictions on Regularized Fisher and Dilatonic Spacetimes Implied by High-Frequency Quasiperiodic Oscillations Observed in Microquasars and Active Galactic Nuclei Open
The Bronnikov generalization of the Fisher naked singularity and Dilatonic black hole spacetimes attracts high interest, as it combines two fundamental transitions of the solutions of Einstein equations. These are the black hole/wormhole “…
View article: A fresh perspective on carp feeding behavior in an aquaculture pond and its consequences for individual growth
A fresh perspective on carp feeding behavior in an aquaculture pond and its consequences for individual growth Open
The common carp (Cyprinus carpio) is an important species in global aquaculture. To optimize its production, it is necessary to understand its behaviour in relation to environmental and management factors. This study investigated the spati…
View article: Two-Decade Changes in the Ciliate Assemblage Feeding Pattern Reflect the Reservoir Nutrient Load
Two-Decade Changes in the Ciliate Assemblage Feeding Pattern Reflect the Reservoir Nutrient Load Open
The perception of the importance of ciliate in freshwater has changed dramatically since the “microbial loop” conceptualisation, reflecting methodological attempts. The data from two decades (1994–2018) on the surface (0–3 m) ciliate assem…
View article: A stoichiometric insight into the seasonal imbalance of phosphorus and nitrogen in central European fishponds
A stoichiometric insight into the seasonal imbalance of phosphorus and nitrogen in central European fishponds Open
Background This study examines seasonal and regional trends in chlorophyll-a concentrations and the dynamics of nitrogen (N) and phosphorus (P) in 32 fishponds (resulting in 150 pond-year cases) employed for fish production. Fishponds have…
View article: Changes in the Epilimnion Ciliate Assemblage Reflect the Reduction of the Nutrient Load of the Reservoir for Two Decades
Changes in the Epilimnion Ciliate Assemblage Reflect the Reduction of the Nutrient Load of the Reservoir for Two Decades Open
The awareness of ciliate importance in freshwater has changed dramatically in the last decades, reflecting methodological attempts. We analysed two decades (1994-2018) of data on the surface (0-3 m) ciliate assemblage in the Slapy reservoi…
View article: Top-down and bottom-up control of plankton structure and dynamics in hypertrophic fishponds
Top-down and bottom-up control of plankton structure and dynamics in hypertrophic fishponds Open
We investigated the effects of strong top-down control by high fish stock on structure and seasonal dynamics of plankton in nine fishponds under conventional fishery management based on auxiliary feeding during two vegetation seasons. Mean…
View article: Seasonal dynamics in microbial plankton reveals the ecological importance of fungi in shallow lake food webs
Seasonal dynamics in microbial plankton reveals the ecological importance of fungi in shallow lake food webs Open
Introduction: High-trophy shallow lakes, both natural and artificial, have become the most common type of lentic waterbodies worldwide. They are key for maintaining landscape ecological stability; however, we still have very limited unders…
View article: Aquatic quillworts, <i>Isoëtes echinospora</i> and <i>I. lacustris</i> under acidic stress—A review from a temperate refuge
Aquatic quillworts, <i>Isoëtes echinospora</i> and <i>I. lacustris</i> under acidic stress—A review from a temperate refuge Open
Quillworts ( Isoëtes ) represent highly specialized flora of softwater lakes, that is, freshwater ecosystems potentially sensitive to acidification. In this paper, we combine a review of previous studies and our new results to address unre…
View article: Geodesic Model of HF QPOs Tested for Black Holes in Spacetimes Reflecting the Effect of Surrounding Dark Matter
Geodesic Model of HF QPOs Tested for Black Holes in Spacetimes Reflecting the Effect of Surrounding Dark Matter Open
Using the simple but robust model of a shell of dark matter (DM) around a Schwarzschild black hole (BH), represented by the mass ratio of the shell and BH $ΔM/M$, the shell extension $Δr_s$ and its inner radius $r_s$, we study the influenc…
View article: Seasonal Development of Phytoplankton in South Bohemian Fishponds (Czechia)
Seasonal Development of Phytoplankton in South Bohemian Fishponds (Czechia) Open
Fishponds with a relatively small water volume, high fish abundance, and wide range of nutrient concentrations serve as suitable models for ecological studies. Intensified fish production, together with increased input of nutrients from th…
View article: The concept of balanced fish nutrition in temperate European fishponds to tackle eutrophication
The concept of balanced fish nutrition in temperate European fishponds to tackle eutrophication Open
The present work aimed to understand nutrient enrichment and resultant eutrophication caused by carp farming in semi-intensively managed, temperate shallow-lake ecosystems like central European fishponds – combining animal nutrition and pl…
View article: Complex effects of acidification, habitat properties and fish stock on littoral macroinvertebrate assemblages in montane standing waters
Complex effects of acidification, habitat properties and fish stock on littoral macroinvertebrate assemblages in montane standing waters Open
Littoral macroinvertebrates in acidified waterbodies are affected by the interaction of acidification and local environmental conditions. Understanding the interplay of these factors in the structuring of communities is essential for inter…
View article: Habitat deterioration despite protection: long-term declines of littoral area of fishponds in Czech nature reserves
Habitat deterioration despite protection: long-term declines of littoral area of fishponds in Czech nature reserves Open
Fishponds play a key role in current pondscapes in many developed countries. Their littoral areas, supporting multiple ecosystem functions including the maintenance of aquatic and riparian biodiversity, have been adversely affected by the …
View article: <scp>CARD‐FISH</scp> and prey tracer techniques reveal the role of overlooked flagellate groups as major bacterivores in freshwater hypertrophic shallow lakes
<span>CARD‐FISH</span> and prey tracer techniques reveal the role of overlooked flagellate groups as major bacterivores in freshwater hypertrophic shallow lakes Open
Summary Heterotrophic nanoflagellates (HNF) and ciliates are major protistan planktonic bacterivores. The term HNF, however, describes a functional guild only and, in contrast to the morphologically distinguishable ciliates, does not refle…
View article: Epicyclic orbits in the field of Einstein-Dirac-Maxwell traversable\n wormholes applied to the quasiperiodic oscillations observed in microquasars\n and active galactic nuclei
Epicyclic orbits in the field of Einstein-Dirac-Maxwell traversable\n wormholes applied to the quasiperiodic oscillations observed in microquasars\n and active galactic nuclei Open
We study the epicyclic oscillatory motion around circular orbits of the\ntraversable asymptotically flat and reflection-symmetric wormholes obtained in\nthe Einstein-Dirac-Maxwell theory without applying exotic matter in their\nconstructio…
View article: Trapping of null geodesics in slowly rotating extremely compact Tolman\n VII spacetimes
Trapping of null geodesics in slowly rotating extremely compact Tolman\n VII spacetimes Open
Region of trapped null geodesics hidden inside of extremely compact objects\nis of astrophysical importance because of trapping of gravitational waves, or\nneutrinos. The trapping effect of null geodesics was extensively studied for\nspher…
View article: Insight into Unprecedented Diversity of Cyanopeptides in Eutrophic Ponds Using an MS/MS Networking Approach
Insight into Unprecedented Diversity of Cyanopeptides in Eutrophic Ponds Using an MS/MS Networking Approach Open
Man-made shallow fishponds in the Czech Republic have been facing high eutrophication since the 1950s. Anthropogenic eutrophication and feeding of fish have strongly affected the physicochemical properties of water and its aquatic communit…
View article: Insight Into Unprecedented Diversity of Cyanopeptides in Eutrophic Ponds Using a MS/MS Networking Approach
Insight Into Unprecedented Diversity of Cyanopeptides in Eutrophic Ponds Using a MS/MS Networking Approach Open
Man-made shallow fishponds in the Czech Republic have been facing a high eutrophication since 1950s. Anthropogenic eutrophication and feeding of fish have strongly affected the physico-chemical properties of water and its aquatic community…
View article: Nutrient footprint and ecosystem services of carp production in European fishponds in contrast to EU crop and livestock sectors
Nutrient footprint and ecosystem services of carp production in European fishponds in contrast to EU crop and livestock sectors Open
There have been some arguments concerning supplementary feed (cereals) based common carp production in fishponds and water pollution, mostly in Central Europe. Using Czech Republic (top producer in EU) as a benchmark and combining data on …
View article: Microbial food webs in hypertrophic fishponds: Omnivorous ciliate taxa are major protistan bacterivores
Microbial food webs in hypertrophic fishponds: Omnivorous ciliate taxa are major protistan bacterivores Open
Despite the importance of shallow lakes worldwide, knowledge of microbial components, the base of their food webs, remains scarce. To close this gap, we investigated planktonic microbial food webs, in particular protistan bacterivory (for …
View article: Effects of tree dieback on lake water acidity in the unmanaged catchment of Plešné Lake, Czech Republic
Effects of tree dieback on lake water acidity in the unmanaged catchment of Plešné Lake, Czech Republic Open
Terrestrial exports of protons (H + ), nitrate (NO 3 − ), dissolved organic carbon including organic acid anions (A − ), phosphorus (P), base cations, and ionic aluminum (Al i ) underwent pronounced changes after bark beetle‐induced tree d…
View article: An Experimental Insight into Extracellular Phosphatases – Differential Induction of Cell-Specific Activity in Green Algae Cultured under Various Phosphorus Conditions
An Experimental Insight into Extracellular Phosphatases – Differential Induction of Cell-Specific Activity in Green Algae Cultured under Various Phosphorus Conditions Open
Extracellular phosphatase activity (PA) has been used as an overall indicator of P depletion in lake phytoplankton. However, detailed insights into the mechanisms of PA regulation are still limited, especially in the case of acid phosphata…
View article: European Red List of Lycopods and Ferns
European Red List of Lycopods and Ferns Open
In recent years, awareness has risen surrounding the crucial role of plants in providing ecosystem services and on their decline – they are one of the essential foundations of healthy ecosystems that we depend on. However, significant gaps…