Michal Šorf

Michal Šorf
Mendel University in Brno · Department of Zoology, Fisheries, Hydrobiology and Apiculture

PhD.

About

37
Publications
13,735
Reads
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429
Citations
Citations since 2017
21 Research Items
361 Citations
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
Additional affiliations
March 2015 - present
University of South Bohemia in České Budějovice
Position
  • PostDoc Position
February 2007 - February 2014
University of South Bohemia in České Budějovice
Position
  • PhD Student

Publications

Publications (37)
Article
Factors affecting the seasonal succession of plankton communities in freshwater temperate lakes have been thoroughly studied for decades. However, there are still relatively few data describing the winter season patterns in detail, as the focus has been mostly on spring to autumn conditions. Ice cover is often the crucial factor limiting light avai...
Article
Planktivorous undesirable fish may threaten both fishpond ecosystem functioning and common carp (Cyprinus carpio) farming. The present study revealed a mechanistic understanding of the adverse ecosystem and production impacts that topmouth gudgeon (Pseudorasbora parva), an invasive omnivorous fish species from Asia, could represent for eutrophic fi...
Article
Clinoptilolite, a natural zeolite, has been added to animal diets to enhance various production parameters. We conducted a feeding experiment, with subsequent stress treatment (lowered oxygen levels), to assess its effect on haematological and biochemical parameters in rainbow trout (Oncorhynchus mykiss). Our results indicated no significant effect...
Article
Full-text available
Plants play an important role in fishpond littorals, but little is known about factors influencing their presence and growth patterns. We surveyed vegetation of reed bed and exposed bottom zones in ponds used for rearing of common carp fry (nursery pond) and ongrowing to market size (main pond). Plant species diversity and functional diversity and...
Article
Full-text available
Pathways of photochemical degradation of a cardiovascular drug verapamil under conditions relevant to natural waters and the toxicity of the photoproducts to Daphnia magna were investigated. Photodegradation was shown to proceed via photocatalysed mechanism. Two main photodegradation pathways were recognised: the first leading to hydroxylation at t...
Article
Full-text available
Submerged macrophytes are of key importance for the structure and functioning of shallow lakes and can be decisive for maintaining them in a clear water state. The ongoing climate change affects the macrophytes through changes in temperature and precipitation, causing variations in nutrient load, water level and light availability. To investigate h...
Article
Full-text available
The aim of this study was to evaluate the ability of a bacterial-enzymatic preparation to affect water quality, particularly the composition and the amount of sediments in ponds. The PTP Plus preparation was applied during the year 2016. For evaluation of the possible effects of the preparation, the water and sediment was compared in the growing se...
Article
The top-down effect of fish predation on reproduction success of Daphnia females was investigated in an outdoor mesocosm experiment with natural (oligotrophic) food conditions. The planktivorous fish, sunbleak (Leucaspius delineatus, 4.9 individuals m -3) was introduced into a half of mesocosms after the first sampling of zooplankton to compare dap...
Article
The spatial distribution of suitable habitats and dispersal abilities of the constituent taxa jointly affect the structure of metacommunities in standing freshwaters. Most studies exploring spatial effects on aquatic metacommunities, however, focus on at most a few taxonomic groups. Within two consecutive seasons, we studied spatial patterns in the...
Preprint
Full-text available
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 both ciliates and heterotrophic nanoflagellates [HNF]), in 10 shallow hypertrophic fishponds in South Bohemia (...
Article
Full-text available
Usage of atrazine, a widely used herbicide, is now banned in many countries. Although forbidden to use, significant concentration of this herbicide is still present in the environment. The study focused not only on the toxicity of atrazine itself but also on products of homogeneous photocatalytic degradation. Such degradation was very fast in given...
Article
Full-text available
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 both ciliates and heterotrophic nanoflagellates [HNF]), in 10 shallow hypertrophic fishponds in South Bohemia (...
Data
Just a link to Open Access: https://aslopubs.onlinelibrary.wiley.com/doi/epdf/10.1002/lno.11260
Article
https://www.sciencedirect.com/science/article/pii/S030437701930066X?dgcid=coauthor
Article
Important drivers of gross primary production (GPP) and ecosystem respiration (ER) in lakes are temperature, nutrients, and light availability, which are predicted to be affected by climate change. Little is known about how these three factors jointly influence shallow lakes metabolism and metabolic status as net heterotrophic or autotrophic. We co...
Article
Full-text available
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 phosphatases. The novel substrate ELF97 phosphate allows for tagging PA on single cells in an epifluorescence microscope...
Article
Key life history parameters significantly differed between two different clones of Simocephalus vetulus originated from different habitats, fishless pool and fish pond. The following fitness-related traits were studied: lifespan, age at first reproduction, interclutch period, number of clutches, and number of embryos. In general, the pool clone rev...
Article
Full-text available
Lentic ecosystems act as sentinels of climate change, and evidence exists that their sensitivity to warming varies along a latitudinal gradient. We assessed the effects of nutrient and water level variability on zooplankton community composition, taxonomic diversity and size structure in different climate zones by running a standardised controlled...
Article
Water chemistry and fish occurrence in outflows from two lakes recovering from acidification were studied during 2005-2010. The two lakes represented the regional extremes: while Lake Laka (LA) was the least acidified among the Bohemian Forest lakes, Lake Čertovo (CT) was the most acidified. Water chemistry improved downstream in either outlet due...
Book
Full-text available
Freshwater reservoirs are water bodies of special interest, as they provide various ecosystem services such as the supply of drinking water, agricultural irrigation, industrial and cooling water supplies, power generation, flood control and recreation. Reservoirs share many features with natural lakes but differ from them in several important aspec...
Article
Full-text available
Losses of phosphorus (P) and nitrogen (N) have important influences on in-lake concentrations and nutrient loading to downstream ecosystems. We performed a series of mesocosm experiments along a latitudinal gradient from Sweden to Greece to investigate the factors influencing N and P loss under different climatic conditions. In six countries, a sta...
Article
Aerobic Anoxygenic Phototrophic (AAP) bacteria are bacteriochlorophyll (BChl) a -containing organisms which use light energy to supplement their predominantly heterotrophic metabolism. Here, we investigated mortality and growth rates of AAP bacteria in three different freshwater lakes in Central Europe: the mountain lake Plešné, the oligo-mesotroph...
Article
1. The response of planktonic (phytoplankton, ciliates, rotifers and crustaceans) and littoral (Ephemeroptera, Plecoptera, Trichoptera and Heteroptera: Nepomorpha) assemblages to chemical recovery was studied over a twelve-year period (1999–2011) in eight glacial lakes in the Bohemian Forest (central Europe). The region suffered from high atmospher...
Article
Periphyton communities play an important role in shallow lakes and are controlled by direct forces such as temperature, light, nutrients, and invertebrate grazing, but also indirectly by planktivorous fish predation. We performed a pan-European lake mesocosm experiment on periphyton colonization covering five countries along a north/south geographi...
Article
The likelihood of an ecological system to undergo undesired regime shifts is expected to increase as climate change effects unfold. To understand how regional climate settings can affect resilience; i.e., the ability of an ecosystem to tolerate disturbances without changing its original structure and processes, we used a synchronized mesocosm exper...
Article
Full-text available
Zooplankton community response to the combined effects of nutrients and fish (hereafter N-F) at contrasting temperatures was studied in a long-term experiment conducted in 24 shallow lake mesocosms with low and high nutrient levels. We found a positive effect of N-F on zooplankton biomass, chlorophyll-a and turbidity. In contrast, zooplankton speci...
Article
Full-text available
Zooplankton seasonal dynamics in the limnetic and littoral zones of Vydymáček pond was studied during the season 2012. Vydymáček is a small (ca 0,88 ha), slightly dystrophic pond and belongs to the Bolevec pond system (Western Bohemia, Czech Republic). The zooplankton occurrence was probably influenced by relatively low pH (seasonal mean from April...
Article
Climate change is expected to profoundly affect both temperature and net precipitation, with implications for lake water level. We describe the design of a harmonized, simultaneous, cross-European mesocosm experiment to elucidate the effects of climate change on community structure, functioning, and metabolism in shallow lakes at low and high nutri...
Article
Full-text available
The impact of fish and cyclopoid copepod predation on zooplankton communities was evaluated using large-volume mesocosms (depth 9.5 m; volume 13 m3) in the Rˇ ı´mov reservoir (Czech Republic). Two yearling roach and perch individuals introduced into mesocosms represented the fish treatment, which was compared to cyclopoid copepods (initial abundanc...
Article
Full-text available
Mesocosms represent a helpful tool enabling in situ experiments within the pelagic zone of lakes and reservoirs. Experimental studies using mesocosms are widely used in shallow lakes. Here, we describe an improved method suitable for deep freshwater ecosystems. We use a metal supporting framework carrying four polyethylene bags (circular cross-sect...
Article
Full-text available
1. We followed microbial and other planktonic communities during a 4-month period (February–May) in 12 outdoor flow-through mesocosms designed to elucidate the effect of global warming and nutrient enrichment. The mesocosms were established in 2003. 2. Warming had a smaller effect than nutrients on the biomass of the microbial and planktonic commu...
Article
We studied potentially omnivorous feeding of the common limnetic calanoid copepod Eudiaptomus gracilis using feeding experiments with subsequent gut content analysis. Feeding experiments performed with a laboratory culture of the rotifer Brachionus calyciflorus established a daily feeding rate reaching up to 9.8 rotifers per day when a rotifer-only...
Article
Full-text available
Seasonal dynamics of zooplankton were investigated in three different habitats of the shallow and temperate Kačležský pond (Czech Republic) during 2003–2004. The studied habitats included the limnetic zone and two littoral zones, each dominated by a different type of emergent macrophyte, reed grass (Glyceria maxima) and common reed (Phragmites aust...
Article
Cyclopoid copepods collected in the St. Anne water tunnel in a historical mining area in Central Bohemia, Czech Republic, were investigated. Two species were identified: Megacyclops viridis (Jurine, 1820) and Paracyclops fimbriatus (Fischer, 1853). Since there is a lack of recent information on the groundwater fauna in the Czech Republic, this cont...

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Projects

Projects (4)
Project
Main aim: Via analysis of ecosystem services and development of suitable tools for effective communication among various stakeholder groups contribute to sustainable and multifunctional utilisation of South-Bohemian fishpond system. This strongly interdisciplinary project will include (1) analysis of diversity and dynamics of biotic communities in the relation to environment, fishpond use and management, and their changes; (2) analysis of socio-economic relations of fishpond-specific changes, their perception by stakeholders and willingness to support actions towards fishpond biodiversity and multiple ecosystem services maintenance; (3) cooperation with professional fish farmers in order to deepen an awareness of fishpond biodiversity and ecosystem services at this stakeholder group and, using the citizen science methods, to involve them into the research and protection of fishpond ecosystems Funding: From 03/2022 to 02/2025 the project receives a government support in framework of the grant nr. SS05010009, provided by Technology Agency of the Czech Republic (see https://www.tacr.cz/en/technology-agency-of-the-czech-republic/) and Ministry of Environment of the Czech Republic.
Project
Aim of the project is to explore plankton diversity and dynamics, key players and their functional traits, and to estimate primary production, respiration, nutrient mobilisation, and production efficiency in the hypertrophic fishponds that allow refining and testing of general ecological hypotheses. Fishponds are semi-natural, man-controlled, shallow ecosystems used for fish production. Different management results in different ecological states that predestine the fishponds as unique model systems. Nutrient loads and fish overstock have led to fishpond hypertrophy; however, interactions in the plankton communities under such extreme conditions remain unexplored. We are lacking data on primary production, community respiration, diversity and functions of heterotrophic microbial food webs in eutrophic freshwaters, as well as about the effects of fish on their food web structure. We hypothesise that hypertrophic conditions result in net ecosystem heterotrophy, an increase in heterotrophic microbial biomass and nutrient mobilisation, and a decrease in net ecosystem productivity and cost effectiveness. Under the conditions of high (auto- and heterotrophic) microbial biomass, intensive photosynthesis and respiration processes cause ecosystem imbalances and low resource use efficiency that results in higher plankton (mainly microbial) diversity due to niche diversification. One of the major research lines of the project is focused on the role of different taxa of freshwater flagellates and ciliates in controlling production of picoplankton, both of heterotrophic bacteria and picocyanobacteria, in hypertrophic shallow fishponds. Hypertrophic fishponds are ideal sites for examining ciliate assemblage composition and bacterivory rates of individual forms. Since these hypertrophic systems are extremely rich in small food particles, such as free living and aggregated bacteria, detrital flocks, autotrophic picoplankton, small algae, and HNF, bacterivory and omnivory are presumably the principal feeding strategies of major ciliate taxa there. For our study we chose ten fishponds, representing a broad variety of hypertrophic study sites. We used a combination of techniques to detect the major ciliate bacterivores and their prevailing feeding modes. To identify taxa we used the classical protargol staining technique. To assess ciliate bacterivory, tracer methods with fluorescently labeled bacteria (FLB) were employed to examine species-specific bacterivory rates, and semi-automated image processing to visualize ingested prey with different optical properties (labeled FLB versus autofluorescing phytoplankton cells). We also estimated bacterivory by HNF using the FLB technique. The aim of the first study (Limnology and Oceanography 2019, doi: 10.1002/lno.11260, currently Open Access available) was to examine the role of ciliates as bacterivores in hypertrophic aquatic systems with two major hypotheses: The aim of our study was to examine the role of ciliates as bacterivores in hypertrophic aquatic systems with two major hypotheses: (i) Small omnivorous ciliate taxa, rather than specialized, primarily bacterivorous ciliates (such as scuticociliates), are major bacterivores in hypertrophic habitats. (ii) There is a general trend of increasing ciliate bacterivory relative to HNF bacterivory along the trophic gradient towards hypertrophic systems. Fist outcome: Šimek K., Grujčić V., Nedoma J., Jezberová J., Šorf M., Matoušů A., Pechar L., Posch T., Bruni E. P., Vrba J. 2019: Microbial food webs in hypertrophic fishponds: omnivorous ciliate taxa are major protistan bacterivores. Limnol. Oceanogr., doi: 10.1002/lno.11260. Šimek K., Mukherjee I., Nedoma J., Paula C. C. P., Jezberová J., Sirová D., Vrba J. CARD-FISH and prey tracer techniques reveal the role of overlooked protistan groups as major bacterivores in hypertrophic ponds. Environ. Microbiol. (in press). doi:10.1111/1462-2920.15846
Project
The Silva Gabreta project funded by the European Funds for Regional Development (Interreg Bavaria-Czech Rep.) allows to implement a jointly prepared cross-border monitoring of biodiversity and environmental conditions in the Transboundary Parks, Šumava NP and Bavarian Forest NP. The aims of the project are to create a functional infrastructure for the cross-border monitoring network and, for the first time in history, to use standardized modern methods to investigate biodiversity of forests, peat bogs and running waters in both national parks. An important goal of the project is to enable the sharing and joint evaluation of the data from common biodiversity database. Masaryk University (Department of Botany and Zoology) participates as a partner in the monitoring of aquatic biotopes in both national parks. The main topics are: (i) long-term study of the colonisation and development of benthic assemblages in restored streams in the Šumava NP, (ii) monitoring of biodiversity of aquatic invertebrates in natural, drained and restored peat bogs, and (iii) a study focused on the structuring of the macroinvertebrate assemblages in the stream networks of the Große Ohe and Vydra Rivers in the core (non-interventional) zones of both national parks.