Károly Pálffy

Károly Pálffy
Centre for Ecological Research (Hungary)

PhD

About

29
Publications
14,562
Reads
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273
Citations
Introduction
Károly Pálffy currently works at the MTA Centre for Ecological Research in Tihany, Hungary. Károly does research in freshwater ecology, limnology and algal ecophysiology. He has experience in light and epifluorescence microscopy, flow cytometry, primary production measurement, algal taxonomy as well as sound knowledge of statistical analysis using R. His current work is mostly focussed on daily and seasonal variability of functional composition in algal communities, how long-term changes in this variability are related to environmental trends and what consequences it might entail in the dynamics of ecosystem processes.
Additional affiliations
August 2010 - present
Centre for Ecological Research, Hungarian Academy of Sciences
Position
  • phytoplankton ecology
Education
September 2001 - July 2004
Faculty of Agricultural and Food Sciences, University of West Hungary
Field of study
  • microalga ecophysiology
August 1996 - June 2001
Faculty of Forestry, University of West Hungary
Field of study

Publications

Publications (29)
Article
The application of functional approaches in understanding phytoplankton community-level responses to changes in the environment has become increasingly widespread in recent years. Eutrophication is known to cause profound modifications in ecosystem processes; however, the underlying relationships between environmental drivers and phytoplankton dive...
Article
Winter phytoplankton communities in the shallow alkaline pans of Hungary are frequently dominated by picoeukaryotes, sometimes in particularly high abundance. In winter 2012, the ice-covered alkaline Zab-szék pan was found to be extraordinarily rich in picoeukaryotic green algae (42–82 × 106 cells ml−1) despite the simultaneous presence of multiple...
Article
The aim of the present study was to assess the effect of ultraviolet radiation (UVR, 280–400 nm) on phytoplankton primary production in Lake Balaton, a shallow lake with the largest surface area in Central Europe possessing unique optical properties. The experiments were performed in situ in summer 1999 in the western basin with generally higher pr...
Article
Laboratory cultures of Desmodesmus armatus (R. Chod.) Hegew. were grown under different levels of photosynthetically active radiation (PAR) supplemented with 3.75 mW · cm–2 UV-A radiation. Growth rate was monitored daily, chlorophyl-a concentration, total carotenoid content, cell number and the relative abundance of different coenobial forms was de...
Article
The occurrence and importance of photoautotrophic picoplankton (PPP, cells with a diameter <2 μm) was studied along a trophic and salinity gradient in hypersaline lakes of the Transylvanian Basin (Romania). The studied lakes were found to be rich in PPP, with abundances (maximum 7.6 × 106 cells mL−1) higher than in freshwater and marine environment...
Article
A crucial point in current research on plankton ecology is how global warming will change community functioning, which has led to numerous studies addressing the question with a variety of conclusions. We previously observed a long-term increase in the compositional variability of phytoplankton in a large shallow lake with a concurrent rise in mean...
Article
Full-text available
Abundant phytoplankton and bacteria were identified by microscopy and high-throughput 16S rRNA tag Illumina sequencing of samples from water- and ice phases collected during winter at two central European Great Lakes, Balaton and Fertő (Neusiedlersee). Bacterial reads at all sites were dominated (>85%) by Bacteroidetes and Proteobacteria. Amongst p...
Article
Full-text available
Eutrophication is a well‐known problem of global proportions with some easily recognizable and potentially harmful effects on aquatic habitats, but our knowledge on the underlying associated changes in ecosystem functioning is rather limited. Relevant studies suggest that seasonal variability in the functional composition of phytoplankton shows an...
Poster
Full-text available
Complex aquatic environments, such as coastal and inland waters have been experiencing deterioration in water quality due to increased anthropogenic impact and climate change. There is an increased demand to have reliable, fast and continuously available techniques to monitor these waters. Advances in remote sensing technology provides the possibil...
Article
Full-text available
The Ocean and Land Color Instrument (OLCI) onboard Sentinel 3A satellite was launched in February 2016. Level 2 (L2) products have been available for the public since July 2017. OLCI provides the possibility to monitor aquatic environments on 300 m spatial resolution on 9 spectral bands, which allows to retrieve detailed information about the water...
Article
Full-text available
Eutrophication and enhanced external nutrient loading of lakes and seas are most clearly reflected by increased cyanobacterial blooms, which are often toxic. Freshwater cyanobacteria produce a number of bioactive secondary metabolites, some of which have allelopathic properties, significantly influencing the biological processes of other algae, the...
Article
Full-text available
Autotrophic picoplankton (APP) abundance and contribution to phytoplankton biomass was studied in Hungarian shallow lakes to test the effect of inorganic turbidity determining the size distribution of the phytoplankton. The studied lakes displayed wide turbidity (TSS: 4–2250 mg l-1) and phytoplankton biomass (chlorophyll a: 1–460 μg l-1) range, as...
Data
Supplementary material on measured parameters. Organic matter free suspended solid concentration (TSS-Org), chlorophyll a concentration and autotrophic picoplankton (APP) abundance, biomass and contribution to total phytoplankton biomass in the studied lakes. (PDF)
Data
Diagnostic plots of linear regression models. Assumptions of linear regressions (i.e homoscedasticity and normality of residuals) and lack of influential points were checked by drawing the standard diagnostic plots of R. (PDF)
Article
Studies on autotrophic picoplankton (APP; < 3 μm) in shallow lakes are mainly confined to the spring through fall seasons, when sampling efforts are not complicated by adverse and unsafe conditions that occur during winter. The aim of the present work was to study the role and diversity of winter APP communities in temperate shallow lakes by means...
Article
Full-text available
Increased external nutrient loads of anthropogenic origin, especially those of phosphorus (P), were one of the major causes of eutrophication during the first half of the twentieth century in Europe. They led to deterioration of lake ecosystems, particularly including noxious blooms of (potentially toxic) cyanobacteria. From the 1970–1980s, strateg...
Conference Paper
Full-text available
In recent years, phenology has been proposed as an indicator to monitor systematically the state of the ecosystem and to detect changes triggered by perturbation of the environmental conditions. Recorded changes in the seasonal timing allowed to evaluate re-organizations of communities and drastic alterations of the ecosystem structure. The Europea...

Questions

Questions (3)
Question
I have flow cytometric data from a series of phytoplankton samples. I organized all the FCS files into flowSets using the flowCore package. My next step would be to determine compositional differences between the samples. The flowCore package offers some options for basic operations on the data, such as gating, subsetting, etc, but now I wonder if there are any more sophicticated packages for a more in-depth analysis. Any suggestions or experience shared would be highly appreciated!
Question
We frequently experience a strange peak in the forward scatter data acquired with a Partec CyFlow Space cytometer and we have no idea as to what the cause for that might be. We tried various samples, even prefiltered MQ water with various sheath fluids, but the outcome remained the same. Running the cleaning fluid provided by the manufacturer seems to solve the problem, but as soon as anything else enters the flow cell, the peak reappears. This is particularly troublesome in dot plots, e.g. a fluorescence channel vs forward scatter, where the peak distorts the image of a population. Has anyone experienced similar problems or has any idea for a solution? Could this be an instrumentation fault or a physical phenomenon I am not familiar with? Any help would be highly appreciated. I attached a histogram and a dot plot for demonstration.
Question
I have been experiencing problems with the flow cytometric detection of bacteria from freshwater samples for some time. Although I have only tried two DNA stains so far: DAPI and HOECHST 33342. My major problem is that the stained samples either yield no discernible fluorescence at all, or the signal is too weak to be distinguished from the background noise. I fixed the samples with formalin and followed the staining protocols found either in the literature or provided by Molecular Probes. We have a Partec CyFlow Space sorter with a UV-led, so after all my failures I began to think that maybe the led is not working properly, but this still has to be checked by the manufacturer. At present I am completely puzzled. Any suggestion would be highly appreciated.

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