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Judit Padisák - One of the best experts on this subject based on the ideXlab platform.
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New, old and evergreen frontiers in freshwater Phytoplankton Ecology: the legacy of Colin S. Reynolds
Hydrobiologia, 2020Co-Authors: Luigi Naselli-flores, Martin T. Dokulil, J. Alex Elliott, Judit PadisákAbstract:This paper offers a brief overview of the contributions provided by widely recognised Phytoplankton ecologists to honour the memory of an undisputed leader in the field of aquatic sciences: Colin S. Reynolds. Colin passed away quite unexpectedly in December 2018 causing a wave of sorrow that rapidly circulated among friends and colleagues all over the world. The 14 review papers collected in this Special Issue form a tribute to Colin’s scientific thinking, which survives the man and represents a legacy to all the scientists in the field, especially to young generations. Although authors and editors carefully selected 14 different topics, a certain degree of overlap exists among the collected contributions. This, far from being a limit, further underlines the holistic nature of Colin’s vision about Phytoplankton and shows the need to develop a comprehensive cultural framework when analysing this complex ecological group of organisms.
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Functional classifications and their application in Phytoplankton Ecology
Freshwater Biology, 2014Co-Authors: Nico Salmaso, Luigi Naselli-flores, Judit PadisákAbstract:SUMMARY 1. Ecologists often group organisms based on similar biological traits or on taxonomic criteria. However, the use of taxonomy in Ecology has many drawbacks because taxa may include species with very different ecological adaptations. Further, similar characters may evolve independently in different lineages. 2. In this review, we examine the main criteria that have been used in the identification of nine modes of classifying Phytoplankton non-taxonomically. These approaches are based purely on morphological and/or structural traits, or on more complex combinations including physiological and ecological features. 3. Different functional approaches have proved able to explain some fraction of the variance observed in the spatial and temporal distribution patterns of algal assemblages, although their effectiveness varies greatly, depending on the number and characteristics of functional traits used. The attribution of functional traits to single species or broad groups of species has allowed a few classifications (e.g. Functional Groups, FG) to be used in the assessment of ecological status. 4. We stress that the misuse of functional classifications (by applying them under conditions other than those intended) can have serious consequences for interpreting ecological processes. Assigning functional traits or groups cannot be considered a surrogate for the knowledge of species or ecotypes, and the use of specific traits must always be justified and circumscribed within the limits of ecological questions and hypotheses. 5. An important future challenge will be to integrate advances in molecular genetics, metabolomics and physiology with more conventional traits; this will form the basis of the next generation of functional classifications.
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Role of atelomixis in replacement of Phytoplankton assemblages in Dom Helvécio Lake, South-East Brazil
Hydrobiologia, 2008Co-Authors: Maria Betânia G. Souza, Cristiane F. A. Barros, Francisco A. R. Barbosa, Éva Hajnal, Judit PadisákAbstract:Scale and frequency of changes in a lake’s physical structure, light dynamics, and availability of nutrients are closely related to Phytoplankton Ecology. Since Phytoplankton assemblages were first described, Phytoplankton ecologists concluded that these assemblages provide insight into Phytoplankton responses to environmental changes. Objectives of this study were to investigate Ecology of Phytoplankton during a complete hydrological cycle in the deepest natural lake in Brazil, Dom Helvecio, and to sort species into the list of assemblages, checking its accordance with environmental changes in a tropical system within the middle Rio Doce Lake district, South-East Brazil. Canonical Correspondence Analysis, t-test, Mann–Whitney U-test, and Kruskal–Wallis test were used to analyze climatological, environmental, and plankton data, which were obtained monthly in 2002. A new Phytoplankton assemblage, NA (atelomixis-dependent desmids), is suggested because atelomixis (robust movement of water occurring once a day) contributed to replacement of species in Dom Helvecio Lake. Stability of stratification, water chemistry, and composition of Phytoplankton assemblages characterized two periods. The first period occurred in six rainy months (Jan–Mar and Oct–Dec) when the lake was stratified and Phytoplankton was dominated by two assemblages: NA and F. The second period occurred in six dry months (Apr–Sep) when the lake was nonstratified and Phytoplankton was dominated by four assemblages: S2, X1, A, and LO. Results suggest that Phytoplankton in Dom Helvecio Lake was shaped by seasonal and daily changes of water temperature, even with its lower amplitude of variation within 2002 (El Nino year). These changes promoted water column stratification or mixing, reduced light, and increased nutrient availability. Temperature, therefore, is similarly important to Phytoplankton Ecology in tropical regions as it is in temperate ones. Sorting Phytoplankton species into assemblages matched well with environmental changes and periods identified so it is also suggested that this can be further used as an appropriate tool to manage water quality when evaluating tropical lakes.
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Shape and size in Phytoplankton Ecology: do they matter?
Hydrobiologia, 2007Co-Authors: Luigi Naselli-flores, Judit Padisák, Meriç AlbayAbstract:This paper summarises the outcomes of the 14th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: morphological and morpho-functional descriptors of Phytoplankton, size and shape structure of Phytoplankton related to different kinds of environmental variables and the role of morphological and physiological plasticity of Phytoplankton in maintaining the (apparently) same populations under different environmental conditions. Case studies from different kinds of aquatic environments (deep and shallow lakes, reservoirs with different age, purpose and trophic state, floodplain wetlands mostly in the temperate region but also from subtropical and tropical ones) have shown that similar environmental forcing calls for similar morpho-functional properties even though the corresponding associations can be markedly different on species level.
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Use of Phytoplankton Assemblages for Monitoring Ecological Status of Lakes within the Water Framework Directive: The Assemblage Index
Hydrobiologia, 2006Co-Authors: Judit Padisák, Gábor Borics, István Grigorszky, Éva Soróczki-pintérAbstract:On basis of recent developments in Phytoplankton Ecology an assemblage index, Q, was developed to assess ecological status of different lake types established by the Water Framework Directive (WFD). Since 5 ≥ Q ≥ 0, the developed index can provide 5-grade qualification required by WFD. Case studies from very different lake types support the usefulness of the developed index. Straights and weaknesses of the Q index for monitoring purposes are discussed. Without arguing for the superiority of the assemblage index in comparison with any other measures of ecological status of lakes, we aim to open a discussion about its possible applications.
Ingrid Chorus - One of the best experts on this subject based on the ideXlab platform.
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equilibrium steady state concept in Phytoplankton Ecology
Hydrobiologia, 2003Co-Authors: Luigi Naselliflores, Judit Padisák, Martin T. Dokulil, Ingrid ChorusAbstract:This paper summarises the outcomes of the 13th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: the effect of trophic state on the attainment of a steady-state; the establishment of equilibria in deep and shallow lakes; the role of spatial heterogeneity, disturbance, and stress in the establishment of equilibrium assemblages; the mechanisms leading to the steady state; the frequency and longevity of equilibrium phases, and the role of morphological and physiological plasticity of Phytoplankton in maintaining the (apparently) same populations under different environmental conditions. The composition of steady-state assemblages is compared to that of Phytoplankton functional groups (coda). Those functional associations recognised as steady-state assemblages appear to be strongly K-determined in many instances.
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Equilibrium/steady-state concept in Phytoplankton Ecology
Hydrobiologia, 2003Co-Authors: Luigi Naselli-flores, Judit Padisák, Martin T. Dokulil, Ingrid ChorusAbstract:This paper summarises the outcomes of the 13(th) Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: the effect of trophic state on the attainment of a steady-state; the establishment of equilibria in deep and shallow lakes; the role of spatial heterogeneity, disturbance, and stress in the establishment of equilibrium assemblages; the mechanisms leading to the steady state; the frequency and longevity of equilibrium phases, and the role of morphological and physiological plasticity of Phytoplankton in maintaining the (apparently) same populations under different environmental conditions. The composition of steady-state assemblages is compared to that of Phytoplankton functional groups (coda). Those functional associations recognised as steady-state assemblages appear to be strongly K-determined in many instances
John P Ryan - One of the best experts on this subject based on the ideXlab platform.
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Correction: Ryan, J., et al. Application of the Hyperspectral Imager for the Coastal Ocean to Phytoplankton Ecology Studies in Monterey Bay, CA, USA. Remote Sens. 2014, 6, 1007-1025
Remote Sensing, 2015Co-Authors: Marcos J. Montes, John P Ryan, Curtiss O. Davis, Nicholas B. Tufillaro, Raphael M. KudelaAbstract:Studies of Phytoplankton Ecology in Monterey Bay, CA, USA, using the Hyperspectral Imager for the Coastal Ocean (HICO) and other satellite remote sensing and in-situ observations, were presented in [1]. [...]
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application of the hyperspectral imager for the coastal ocean to Phytoplankton Ecology studies in monterey bay ca usa
Remote Sensing, 2014Co-Authors: John P Ryan, Curtiss O. Davis, Nicholas B. Tufillaro, Raphael M. KudelaAbstract:As a demonstrator for technologies for the next generation of ocean color sensors, the Hyperspectral Imager for the Coastal Ocean (HICO) provides enhanced spatial and spectral resolution that is required to understand optically complex aquatic environments. In this study we apply HICO, along with satellite remote sensing and in situ observations, to studies of Phytoplankton Ecology in a dynamic coastal upwelling environment—Monterey Bay, CA, USA. From a spring 2011 study, we examine HICO-detected spatial patterns in Phytoplankton optical properties along an environmental gradient defined by upwelling flow patterns and along a temporal gradient of upwelling intensification. From a fall 2011 study, we use HICO's enhanced spatial and spectral resolution to distinguish a small-scale ―red tide‖ bloom, and we examine bloom expansion and its supporting processes using other remote sensing and in situ data. From a spectacular HICO image of the Monterey Bay region acquired during fall of 2012, we present a suite of algorithm results for characterization of Phytoplankton, and we examine the strengths, limitations, and distinctions of each algorithm in the context of the enhanced spatial and spectral resolution.
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Boundary influences on HAB Phytoplankton Ecology in a stratification-enhanced upwelling shadow
Deep Sea Research Part II: Topical Studies in Oceanography, 2014Co-Authors: John P Ryan, Francisco P Chavez, James G Bellingham, Raphael M. Kudela, Margaret A. Mcmanus, M. Lara Artigas, Gregory J. Doucette, David G. Foley, Mike Godin, Julio B.j. HarveyAbstract:Coastal marine ecosystems are profoundly influenced by processes that originate from their boundaries. These include fluid boundaries—with the atmosphere, oceanic boundary currents and terrestrial aquatic systems, as well as solid boundaries—with the seafloor and coast. Phytoplankton populations transfer complexly interacting boundary influences into the biosphere. In this contribution, we apply data from an ocean observing and modeling system to examine boundary influences driving Phytoplankton Ecology in Monterey Bay, CA, USA. The study was focused on species that may cause harmful algal blooms (HABs). During September–October 2010, autonomous molecular analytical devices were moored at two locations characterized by different degrees of stratification and exposure to upwelling dynamics. The time-series revealed multiple transitions in local HAB Phytoplankton communities, involving diatoms (Pseudo-nitzschia spp.), dinoflagellates (Alexandrium catenella), and raphidophytes (Heterosigma akashiwo). Observational and model results showed that the biological transitions were closely related to environmental changes that resulted from a variety of boundary processes—responses of oceanic circulation to wind forcing, influxes of different water types that originated outside the bay, and emergence of strongly stratified nearshore water into the greater bay. Boundary processes were further implicated at patch scales. High-resolution mapping and sampling of a Phytoplankton-enriched patch were conducted in a Lagrangian framework using autonomous underwater vehicles. These highly resolved measurements showed that small-scale spatial patterns in the toxicity of Pseudo-nitzschia populations were related to the coupling of resuspended sediments from the bottom boundary layer to the surface mixed layer.
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Harmful Phytoplankton Ecology studies using an autonomous molecular analytical and ocean observing network
Limnology and Oceanography, 2011Co-Authors: John P Ryan, Dianne I. Greenfield, Iii Marin R., C. Preston, Brent Roman, Scott Jensen, Douglas Pargett, James M. Birch, Christina M. Mikulski, Gregory J. DoucetteAbstract:Using autonomous molecular analytical devices embedded within an ocean observatory, we studied harmful algal bloom (HAB) Ecology in the dynamic coastal waters of Monterey Bay, California. During studies in 2007 and 2008, HAB species abundance and toxin concentrations were quantified periodically at two locations by Environmental Sample Processor (ESP) robotic biochemistry systems. Concurrently, environmental variability and processes were characterized by sensors co-located with ESP network nodes, regional ocean moorings, autonomous underwater vehicle surveys, and satellite remote sensing. The two locations differed in their long-term average physical and biological conditions and in their degree of exposure to episodic wind-forced variability. While anomalously weak upwelling and strong stratification during the 2007 study favored toxigenic dinoflagellates (Alexandrium catenella), anomalously strong upwelling during the 2008 study favored toxigenic diatoms (Pseudo-nitzschia spp.). During both studies, raphidophytes (Heterosigma akashiwo) were detected within a similar range of concentrations, and they reached higher abundances at the relatively sheltered, stratified site. During 2008, cellular domoic acid reached higher concentrations and was far more variable at the shallower ESP node, where Phytoplankton populations were influenced by resuspended sediments. Episodic variability caused by wind forcing, lateral mixing, internal waves, and subsurface Phytoplankton layers influenced ESP detection patterns. The results illustrate the importance of mobilizing HAB detection on autonomous platforms that can intelligently target sample acquisition as a function of environmental conditions and biological patch encounter.
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Mapping Phytoplankton in situ using a laser-scattering sensor
Limnology and Oceanography: Methods, 2008Co-Authors: Erich Rienecker, John P Ryan, Marguerite Blum, Caroline Dietz, Luke J. Coletti, Roman Marin, W. Paul BissettAbstract:A primary limitation of Phytoplankton Ecology research is the difficulty of describing patchiness and distributions of different Phytoplankton groups. Chlorophyll fluorescence and optical backscatter are useful measurements that provide information about Phytoplankton, but these measurements do not allow distinction of Phytoplankton taxa. Traditional Phytoplankton identification methods (such as microscopy, HPLC analysis, and flow cytometry) are labor intensive and therefore can provide only very limited coverage and resolution. Through lab experiments we show that the Laser In Situ Scattering and Transmissometer (LISST-100) instrument can accurately quantify Phytoplankton cell dimensions for some cell shapes. Pseudo-spherical dinoflagellates are described with a single peak in the particle size distribution (PSD) at the cross-sectional dimension of the cells. Pennate diatoms are described with peaks in the PSD at the major and minor axis dimensions of the cells. Diatom cells with minor axis dimensions that vary along the major axis are described with one peak across the range of minor axis dimensions and a second peak at the major axis dimension. Through field experiments, we show that mapping the PSD in situ at high resolution permits description of patchiness and evolution of Phytoplankton populations. We present two examples: (1) growing dominance of Ceratium species during a red tide bloom, and (2) concentration of Pseudo-nitzschia australis, a harmful algal bloom (HAB) species, at a water mass front. We conclude that synoptic mapping of the PSD can significantly advance Phytoplankton Ecology research in the coastal ocean.
Martin T. Dokulil - One of the best experts on this subject based on the ideXlab platform.
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New, old and evergreen frontiers in freshwater Phytoplankton Ecology: the legacy of Colin S. Reynolds
Hydrobiologia, 2020Co-Authors: Luigi Naselli-flores, Martin T. Dokulil, J. Alex Elliott, Judit PadisákAbstract:This paper offers a brief overview of the contributions provided by widely recognised Phytoplankton ecologists to honour the memory of an undisputed leader in the field of aquatic sciences: Colin S. Reynolds. Colin passed away quite unexpectedly in December 2018 causing a wave of sorrow that rapidly circulated among friends and colleagues all over the world. The 14 review papers collected in this Special Issue form a tribute to Colin’s scientific thinking, which survives the man and represents a legacy to all the scientists in the field, especially to young generations. Although authors and editors carefully selected 14 different topics, a certain degree of overlap exists among the collected contributions. This, far from being a limit, further underlines the holistic nature of Colin’s vision about Phytoplankton and shows the need to develop a comprehensive cultural framework when analysing this complex ecological group of organisms.
-
equilibrium steady state concept in Phytoplankton Ecology
Hydrobiologia, 2003Co-Authors: Luigi Naselliflores, Judit Padisák, Martin T. Dokulil, Ingrid ChorusAbstract:This paper summarises the outcomes of the 13th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: the effect of trophic state on the attainment of a steady-state; the establishment of equilibria in deep and shallow lakes; the role of spatial heterogeneity, disturbance, and stress in the establishment of equilibrium assemblages; the mechanisms leading to the steady state; the frequency and longevity of equilibrium phases, and the role of morphological and physiological plasticity of Phytoplankton in maintaining the (apparently) same populations under different environmental conditions. The composition of steady-state assemblages is compared to that of Phytoplankton functional groups (coda). Those functional associations recognised as steady-state assemblages appear to be strongly K-determined in many instances.
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Equilibrium/steady-state concept in Phytoplankton Ecology
Hydrobiologia, 2003Co-Authors: Luigi Naselli-flores, Judit Padisák, Martin T. Dokulil, Ingrid ChorusAbstract:This paper summarises the outcomes of the 13(th) Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: the effect of trophic state on the attainment of a steady-state; the establishment of equilibria in deep and shallow lakes; the role of spatial heterogeneity, disturbance, and stress in the establishment of equilibrium assemblages; the mechanisms leading to the steady state; the frequency and longevity of equilibrium phases, and the role of morphological and physiological plasticity of Phytoplankton in maintaining the (apparently) same populations under different environmental conditions. The composition of steady-state assemblages is compared to that of Phytoplankton functional groups (coda). Those functional associations recognised as steady-state assemblages appear to be strongly K-determined in many instances
Raphael M. Kudela - One of the best experts on this subject based on the ideXlab platform.
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Correction: Ryan, J., et al. Application of the Hyperspectral Imager for the Coastal Ocean to Phytoplankton Ecology Studies in Monterey Bay, CA, USA. Remote Sens. 2014, 6, 1007-1025
Remote Sensing, 2015Co-Authors: Marcos J. Montes, John P Ryan, Curtiss O. Davis, Nicholas B. Tufillaro, Raphael M. KudelaAbstract:Studies of Phytoplankton Ecology in Monterey Bay, CA, USA, using the Hyperspectral Imager for the Coastal Ocean (HICO) and other satellite remote sensing and in-situ observations, were presented in [1]. [...]
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application of the hyperspectral imager for the coastal ocean to Phytoplankton Ecology studies in monterey bay ca usa
Remote Sensing, 2014Co-Authors: John P Ryan, Curtiss O. Davis, Nicholas B. Tufillaro, Raphael M. KudelaAbstract:As a demonstrator for technologies for the next generation of ocean color sensors, the Hyperspectral Imager for the Coastal Ocean (HICO) provides enhanced spatial and spectral resolution that is required to understand optically complex aquatic environments. In this study we apply HICO, along with satellite remote sensing and in situ observations, to studies of Phytoplankton Ecology in a dynamic coastal upwelling environment—Monterey Bay, CA, USA. From a spring 2011 study, we examine HICO-detected spatial patterns in Phytoplankton optical properties along an environmental gradient defined by upwelling flow patterns and along a temporal gradient of upwelling intensification. From a fall 2011 study, we use HICO's enhanced spatial and spectral resolution to distinguish a small-scale ―red tide‖ bloom, and we examine bloom expansion and its supporting processes using other remote sensing and in situ data. From a spectacular HICO image of the Monterey Bay region acquired during fall of 2012, we present a suite of algorithm results for characterization of Phytoplankton, and we examine the strengths, limitations, and distinctions of each algorithm in the context of the enhanced spatial and spectral resolution.
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Boundary influences on HAB Phytoplankton Ecology in a stratification-enhanced upwelling shadow
Deep Sea Research Part II: Topical Studies in Oceanography, 2014Co-Authors: John P Ryan, Francisco P Chavez, James G Bellingham, Raphael M. Kudela, Margaret A. Mcmanus, M. Lara Artigas, Gregory J. Doucette, David G. Foley, Mike Godin, Julio B.j. HarveyAbstract:Coastal marine ecosystems are profoundly influenced by processes that originate from their boundaries. These include fluid boundaries—with the atmosphere, oceanic boundary currents and terrestrial aquatic systems, as well as solid boundaries—with the seafloor and coast. Phytoplankton populations transfer complexly interacting boundary influences into the biosphere. In this contribution, we apply data from an ocean observing and modeling system to examine boundary influences driving Phytoplankton Ecology in Monterey Bay, CA, USA. The study was focused on species that may cause harmful algal blooms (HABs). During September–October 2010, autonomous molecular analytical devices were moored at two locations characterized by different degrees of stratification and exposure to upwelling dynamics. The time-series revealed multiple transitions in local HAB Phytoplankton communities, involving diatoms (Pseudo-nitzschia spp.), dinoflagellates (Alexandrium catenella), and raphidophytes (Heterosigma akashiwo). Observational and model results showed that the biological transitions were closely related to environmental changes that resulted from a variety of boundary processes—responses of oceanic circulation to wind forcing, influxes of different water types that originated outside the bay, and emergence of strongly stratified nearshore water into the greater bay. Boundary processes were further implicated at patch scales. High-resolution mapping and sampling of a Phytoplankton-enriched patch were conducted in a Lagrangian framework using autonomous underwater vehicles. These highly resolved measurements showed that small-scale spatial patterns in the toxicity of Pseudo-nitzschia populations were related to the coupling of resuspended sediments from the bottom boundary layer to the surface mixed layer.