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Kathryn L Cottingham - One of the best experts on this subject based on the ideXlab platform.
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The cyanobacterium Gloeotrichia echinulata increases the stability and network complexity of phytoplankton communities
Ecosphere, 2017Co-Authors: Cayelan C. Carey, Bryan L. Brown, Kathryn L CottinghamAbstract:Changes in the abundance of a taxon can have large effects on communities, particularly if that taxon is a strong interactor. These changes may arise as a consequence of environmental change, recruitment from dormant stages, or quirks of population dynamics, and have effects that ripple through a community interaction network. We hypothesized that cyanobacteria, which are increasing in many freshwater lakes globally, may be strong interactors because they can exert large and persistent effects on the biomass and composition of other phytoplankton. To test this hypothesis, we evaluated how the phytoplankton community responded to different densities of Gloeotrichia echinulata, a large colonial cyanobacterium increasingly observed in low-nutrient lakes in northeastern North America, in an in situ mesocosm experiment. We observed that many phytoplankton taxa, especially diatoms and green algae, responded primarily to increased nutrient availability (a result of Gloeotrichia's nitrogen fixation and translocation of phosphorus from the sediments), while a few taxa (two euglenophytes, one dinoflagellate, and one cyanobacterium) responded to both the direct and indirect effects of Gloeotrichia. Surprisingly, Gloeotrichia reduced the compositional variability of the phytoplankton community relative to the non-Gloeotrichia control treatment; there was no effect on the aggregate temporal variability of total non-Gloeotrichia biovolume. Moreover, experimentally increased densities of Gloeotrichia coincided with increasing complexity of the phytoplankton community in network analyses of taxon co-occurrences, as indicated by significantly greater network density and transitivity and shorter path lengths. Taken together, these findings suggest that Gloeotrichia may be a strongly interacting species in low-nutrient lakes, with the potential to increase the resilience of phytoplankton communities to future disturbance by increasing compositional stability and network complexity.
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Trophic state mediates the effects of a large colonial cyanobacterium on phytoplankton dynamics
Fundamental and Applied Limnology, 2014Co-Authors: Cayelan C. Carey, Kathryn L Cottingham, Nelson G. Hairston, Kathleen C. WeathersAbstract:Although cyanobacterial blooms are typically found in eutrophic lakes, where they are able to exert inhibitory effects on other plankton, they are also reported from oligotrophic and mesotrophic lakes. Here, we explored whether trophic state mediates the effects of Gloeotrichia echinulata blooms in freshwater ecosystems. This taxon is a large, colonial cyanobacterium that may be increasing in low-nutrient lakes in northeastern North America. We manipulated Gloeotrichia presence in mesotrophic and eutrophic mesocosms and measured its ef- fects on phosphorus, nitrogen, phytoplankton growth in two size fractions (< 30 µm, and total fraction), and zoo- plankton. In mesotrophic mesocosms, Gloeotrichia stimulated the growth of smaller-sized phytoplankton, poten- tially through significantly higher total nitrogen and phosphorus concentrations than in non-Gloeotrichia controls, although nearly all measured soluble nutrient concentrations were below method detection limits. In contrast, the growth of smaller-sized phytoplankton was inhibited in eutrophic mesocosms, where concentrations of total nitrogen and phosphorus were significantly lower in the presence of Gloeotrichia in comparison to controls. The Gloeotrichia colonies likely inhibited phytoplankton growth in the eutrophic mesocosms by creating scums that decreased light availability, although other mechanisms may be involved. The positive or negative effect of Gloe- otrichia did not cascade to higher trophic levels: zooplankton biomass was significantly higher in the eutrophic than mesotrophic mesocosms, but not affected by Gloeotrichia presence. In summary, trophic state determined if the effects of Gloeotrichia on smaller-sized phytoplankton were stimulatory or inhibitory, likely due to several interacting mechanisms.
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Spatial and temporal variability in recruitment of the cyanobacterium Gloeotrichia echinulata in an oligotrophic lake
Freshwater Science, 2014Co-Authors: Cayelan C. Carey, Holly A. Ewing, Kathleen C. Weathers, Meredith L. Greer, Kathryn L CottinghamAbstract:AbstractRecruitment from dormant stages in the benthos can provide a critically important inoculum for surface populations of phytoplankton, including bloom-forming cyanobacteria. For example, water-column populations of the large (1–3-mm diameter) colonial cyanobacterium Gloeotrichia echinulata (Smith) P. Richter can be strongly subsidized by benthic recruitment. Therefore, understanding controls on recruitment is essential to an investigation of the factors controlling Gloeotrichia blooms, which are increasing in low-nutrient lakes across northeastern North America. We quantified surface abundances and recruitment from littoral sediments at multiple near-shore sampling sites in oligotrophic Lake Sunapee, New Hampshire, USA, during the summers of 2005–2012 and used this data set—the longest known record of cyanobacterial recruitment—to investigate potential drivers of interannual differences in Gloeotrichia recruitment. We found extensive spatiotemporal variability in recruitment. Recruitment was higher ...
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Collaborative Understanding of Cyanobacteria in Lake Ecosystems.
The College Mathematics Journal, 2013Co-Authors: Meredith L. Greer, Holly A. Ewing, Kathryn L Cottingham, Kathleen C. WeathersAbstract:SummaryWe describe a collaboration between mathematicians and ecologists studying the cyanobacterium Gloeotrichia echinulata and its possible role in eutrophication of New England lakes. The mathematics includes compartmental modeling, differential equations, difference equations, and testing models against high-frequency data. The ecology includes observation, field sampling, and parameter estimation based on observed data and the related literature. Mathematically and ecologically, a collaboration like this progresses in ways it never would have if either group worked alone.
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Occurrence and toxicity of the cyanobacterium Gloeotrichia echinulata in low-nutrient lakes in the northeastern United States
Aquatic Ecology, 2012Co-Authors: Cayelan C. Carey, Holly A. Ewing, Kathleen C. Weathers, R. Quinn Thomas, Kathryn L Cottingham, James F. HaneyAbstract:To date, most research on cyanobacterial blooms has focused on high-nutrient, not low-nutrient lakes. We investigated reports of the cyanobacterium Gloeotrichia echinulata in lakes with low concentrations of nitrogen and phosphorus across the northeastern United States by surveying selected oligotrophic and mesotrophic lakes during four summers. G. echinulata is a large (1–3 mm diameter) colonial cyanobacterium that may have substantial effects on low-nutrient lakes used for drinking water and recreation because it can produce the toxin microcystin-LR. We found G. echinulata in the water column of 27 out of 37 lakes we sampled in Maine, New Hampshire, New York, and Vermont. G. echinulata densities were typically low (
Cayelan C. Carey - One of the best experts on this subject based on the ideXlab platform.
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The cyanobacterium Gloeotrichia echinulata increases the stability and network complexity of phytoplankton communities
Ecosphere, 2017Co-Authors: Cayelan C. Carey, Bryan L. Brown, Kathryn L CottinghamAbstract:Changes in the abundance of a taxon can have large effects on communities, particularly if that taxon is a strong interactor. These changes may arise as a consequence of environmental change, recruitment from dormant stages, or quirks of population dynamics, and have effects that ripple through a community interaction network. We hypothesized that cyanobacteria, which are increasing in many freshwater lakes globally, may be strong interactors because they can exert large and persistent effects on the biomass and composition of other phytoplankton. To test this hypothesis, we evaluated how the phytoplankton community responded to different densities of Gloeotrichia echinulata, a large colonial cyanobacterium increasingly observed in low-nutrient lakes in northeastern North America, in an in situ mesocosm experiment. We observed that many phytoplankton taxa, especially diatoms and green algae, responded primarily to increased nutrient availability (a result of Gloeotrichia's nitrogen fixation and translocation of phosphorus from the sediments), while a few taxa (two euglenophytes, one dinoflagellate, and one cyanobacterium) responded to both the direct and indirect effects of Gloeotrichia. Surprisingly, Gloeotrichia reduced the compositional variability of the phytoplankton community relative to the non-Gloeotrichia control treatment; there was no effect on the aggregate temporal variability of total non-Gloeotrichia biovolume. Moreover, experimentally increased densities of Gloeotrichia coincided with increasing complexity of the phytoplankton community in network analyses of taxon co-occurrences, as indicated by significantly greater network density and transitivity and shorter path lengths. Taken together, these findings suggest that Gloeotrichia may be a strongly interacting species in low-nutrient lakes, with the potential to increase the resilience of phytoplankton communities to future disturbance by increasing compositional stability and network complexity.
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Trophic state mediates the effects of a large colonial cyanobacterium on phytoplankton dynamics
Fundamental and Applied Limnology, 2014Co-Authors: Cayelan C. Carey, Kathryn L Cottingham, Nelson G. Hairston, Kathleen C. WeathersAbstract:Although cyanobacterial blooms are typically found in eutrophic lakes, where they are able to exert inhibitory effects on other plankton, they are also reported from oligotrophic and mesotrophic lakes. Here, we explored whether trophic state mediates the effects of Gloeotrichia echinulata blooms in freshwater ecosystems. This taxon is a large, colonial cyanobacterium that may be increasing in low-nutrient lakes in northeastern North America. We manipulated Gloeotrichia presence in mesotrophic and eutrophic mesocosms and measured its ef- fects on phosphorus, nitrogen, phytoplankton growth in two size fractions (< 30 µm, and total fraction), and zoo- plankton. In mesotrophic mesocosms, Gloeotrichia stimulated the growth of smaller-sized phytoplankton, poten- tially through significantly higher total nitrogen and phosphorus concentrations than in non-Gloeotrichia controls, although nearly all measured soluble nutrient concentrations were below method detection limits. In contrast, the growth of smaller-sized phytoplankton was inhibited in eutrophic mesocosms, where concentrations of total nitrogen and phosphorus were significantly lower in the presence of Gloeotrichia in comparison to controls. The Gloeotrichia colonies likely inhibited phytoplankton growth in the eutrophic mesocosms by creating scums that decreased light availability, although other mechanisms may be involved. The positive or negative effect of Gloe- otrichia did not cascade to higher trophic levels: zooplankton biomass was significantly higher in the eutrophic than mesotrophic mesocosms, but not affected by Gloeotrichia presence. In summary, trophic state determined if the effects of Gloeotrichia on smaller-sized phytoplankton were stimulatory or inhibitory, likely due to several interacting mechanisms.
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Spatial and temporal variability in recruitment of the cyanobacterium Gloeotrichia echinulata in an oligotrophic lake
Freshwater Science, 2014Co-Authors: Cayelan C. Carey, Holly A. Ewing, Kathleen C. Weathers, Meredith L. Greer, Kathryn L CottinghamAbstract:AbstractRecruitment from dormant stages in the benthos can provide a critically important inoculum for surface populations of phytoplankton, including bloom-forming cyanobacteria. For example, water-column populations of the large (1–3-mm diameter) colonial cyanobacterium Gloeotrichia echinulata (Smith) P. Richter can be strongly subsidized by benthic recruitment. Therefore, understanding controls on recruitment is essential to an investigation of the factors controlling Gloeotrichia blooms, which are increasing in low-nutrient lakes across northeastern North America. We quantified surface abundances and recruitment from littoral sediments at multiple near-shore sampling sites in oligotrophic Lake Sunapee, New Hampshire, USA, during the summers of 2005–2012 and used this data set—the longest known record of cyanobacterial recruitment—to investigate potential drivers of interannual differences in Gloeotrichia recruitment. We found extensive spatiotemporal variability in recruitment. Recruitment was higher ...
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Occurrence and toxicity of the cyanobacterium Gloeotrichia echinulata in low-nutrient lakes in the northeastern United States
Aquatic Ecology, 2012Co-Authors: Cayelan C. Carey, Holly A. Ewing, Kathleen C. Weathers, R. Quinn Thomas, Kathryn L Cottingham, James F. HaneyAbstract:To date, most research on cyanobacterial blooms has focused on high-nutrient, not low-nutrient lakes. We investigated reports of the cyanobacterium Gloeotrichia echinulata in lakes with low concentrations of nitrogen and phosphorus across the northeastern United States by surveying selected oligotrophic and mesotrophic lakes during four summers. G. echinulata is a large (1–3 mm diameter) colonial cyanobacterium that may have substantial effects on low-nutrient lakes used for drinking water and recreation because it can produce the toxin microcystin-LR. We found G. echinulata in the water column of 27 out of 37 lakes we sampled in Maine, New Hampshire, New York, and Vermont. G. echinulata densities were typically low (
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The cyanobacterium Gloeotrichia echinulata stimulates the growth of other phytoplankton
Journal of Plankton Research, 2010Co-Authors: Cayelan C. Carey, Karin RengeforsAbstract:We tested the effect of the cyanobacterium Gloeotrichia echinulata on a diverse array of phytoplankton. We found that Gloeotrichia increased the growth rates of five of seven phytoplankton species up to 620% in comparison with a medium-only control after 96 h.
Kurt Pettersson - One of the best experts on this subject based on the ideXlab platform.
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recruitment and pelagic growth of Gloeotrichia echinulata cyanophyceae in lake erken1
Journal of Phycology, 2003Co-Authors: Irene Karlssonelfgren, Emil Rydin, Per Hyenstrand, Kurt PetterssonAbstract:Different parameters in the life cycle of the colony forming cyanobacterium Gloeotrichia echinulata (J.E. Smith) Richter was evaluated in Lake Erken, Sweden. Recruitment of colonies from the sediments and pelagic abundance were measured during 2 years. These data were then used in a model to evaluate and estimate parameters of the life cycle. In our study, recruitment alone only contributed to a small part (<5%) of the maximum G. echinulata abundance that occurred during late summer. However, recruitment from shallow sediments forms the important seed for the pelagic population. Together with measured rates of migration from the sediment, variations in either pelagic colony division rate or pelagic residence time could explain variations in the measured abundance of G. echinulata in situ.
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RECRUITMENT AND PELAGIC GROWTH OF Gloeotrichia ECHINULATA (CYANOPHYCEAE) IN LAKE ERKEN1
Journal of Phycology, 2003Co-Authors: Irene Karlsson-elfgren, Emil Rydin, Per Hyenstrand, Kurt PetterssonAbstract:Different parameters in the life cycle of the colony forming cyanobacterium Gloeotrichia echinulata (J.E. Smith) Richter was evaluated in Lake Erken, Sweden. Recruitment of colonies from the sediments and pelagic abundance were measured during 2 years. These data were then used in a model to evaluate and estimate parameters of the life cycle. In our study, recruitment alone only contributed to a small part (
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On the seasonal migration of the cyanobacterium Gloeotrichia echinulata in Lake Erken, Sweden, and its influence on the pelagic population
Marine and Freshwater Research, 1995Co-Authors: Lena Forsell, Kurt PetterssonAbstract:The quantity and distribution of colonies of Gloeotrichia echinulata migrating from the sediments into the water column were studied in Lake Erken by the use of inverted traps. The epilimnetic population and the phosphorus status of the epilimnetic colonies were quantified. The numbers of colonies in the traps were greatest in the shallower areas. As the stratification became weaker and the epilimnetic population declined, the amount of colonies in all the traps increased markedly. Most of the colonies in the traps were due to redistribution within the water column. On the assumption that no epilimnetic uptake of phosphorus occurred in G. echinulata, the internal loading of phosphorus due to migrating colonies was calculated to be between 0.4 and 0.6 mg P m-2 day-1 during July and August. The proportion of newly migrated colonies in the epilimnetic G. echinulata population was calculated to be around 50% for the period before the epilimnetic population maximum. The increasing phosphorus content of the epilimnetic colonies after the population maximum indicates that the migration continued even after this.
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The role of Gloeotrichia echinulata in the transfer of phosphorus from sediments to water in Lake Erken
Hydrobiologia, 1993Co-Authors: Kurt Pettersson, Eva Herlitz, Vera IstvánovicsAbstract:The abundance of Gloeotrichia echinulata colonies in the sediments of Lake Erken and their phosphorus content were investigated to determine the contribution of Gloeotrichia colonies to total sediment phosphorus. Moreover, the potential size of the algal inoculum and the migration to the water during summer were estimated.
Kaarina Sivonen - One of the best experts on this subject based on the ideXlab platform.
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strains of the cyanobacterial genera calothrix and rivularia isolated from the baltic sea display cryptic diversity and are distantly related to Gloeotrichia and tolypothrix
FEMS Microbiology Ecology, 2007Co-Authors: Leila M Sihvonen, Christina Lyra, Pirjo Rajaniemiwacklin, Jaana M Lehtimaki, Matti Wahlsten, David P Fewer, Kaarina SivonenAbstract:Strains of the cyanobacterial genus Calothrix display pronounced tapering filaments. These cyanobacteria are benthic, have a worldwide distribution and are among the most easily recognizable cyanobacterial genera. However, it is not clear whether cyanobacterial strains assigned to the genus Calothrix constitute a natural monophyletic group. We sequenced 16S rRNA genes from 42 cyanobacterial cultures and environmental samples belonging to the genus Calothrix, and the morphologically similar genera Rivularia, Gloeotrichia and Tolypothrix. Phylogenetic analysis of the 16S rRNA gene identified large sequence diversity among the Calothrix morphotype strains. Our results demonstrate that Calothrix, Gloeotrichia and Tolypothrix do not form a monophyletic group but instead display a high level of genetic diversity. The evolutionary distances between cyanobacteria, morphologically identified as Calothrix, suggest that they belong to at least five different genera. Our results also suggest that the genus Gloeotrichia is distantly related to the genus Calothrix. We found correlations between genetic grouping and morphology in redundancy analysis. However, morphology alone was not sufficiently reliable to distinguish strains from different 16S rRNA gene clusters. The high level of diversity that we observed confirms the hypothesis that the Rivulariaceae are species rich.
Per Hyenstrand - One of the best experts on this subject based on the ideXlab platform.
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Pelagic growth and colony division of
2015Co-Authors: Irene Karlsson-elfgren, Per Hyenstrand, Emil RiydinAbstract:Gloeotrichia echinulata colony development was monitored in Lake Erken, Sweden and studied in enclosure experiments. Significant colonial division did not occur in mesh bags, although the abundance of the pelagic population in the lake increased during the experimental periods. On the basis of these findings, it is suggested that circulation of G. echinulata to deeper nutrient rich water supports pelagic growth. In support of this, a large part of the buoyant G. echinulata colonies in Lake Erken was found at several meters depth. In an experiment with nutrient additions, the only treatment that favoured G. echinulata development was additions of phosphate, nitrate and iron. Trace element additions had a negative effect on the development of G. echinulata. On the basis of these findings, the nutritional requirements of G. echinulata are discussed
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Pelagic growth and colony division of Gloeotrichia echinulata in Lake Erken
Journal of Plankton Research, 2004Co-Authors: Irene Karlsson-elfgren, Per Hyenstrand, Emil RiydinAbstract:Cyanobacteria which can form resting cells (in this case akinetes) are common in meso-eutrophic lakes in temperate regions, often dominating the phytoplankton communities during summer. The life cycles of akinete-forming cyanobacteria has been studied with Gloeotrichia echinulata as a model organism. Anabaena and Aphanizomenon were also included in a migration study. The focus of this thesis has been the factors influencing the processes of germination and subsequent growth, the factors influencing migration from the sediment, and the amount of growth occurring in the water. Germination of G. echinulata was strongly favoured by light, and recruitment was highest from organic-rich sediments in shallow, sheltered littoral areas, between 0-3 m. Recruitment of Anabaena and Aphanizomenon was less light dependent, yet the highest recruitment occurred from shallow sediments (0-2 m). This means that organic-rich sediments (0-3 m) in shallow areas are the most important seed-banks of akinete-forming cyanobacteria. The inocula contributed only to a minor extent to the maximum pelagic populations. 4% for G. echinulata in the mesotrophic Lake Erken, and 0.03% for both Anabaena and Aphanizomenon in the eutrophic Lake Limmaren. This implies that processes of growth and division in the water are important for the maximum size of the pelagic population. Prolonged recruitment from the sediment strongly promoted establishment of the species in the water, especially G. echinulata.
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recruitment and pelagic growth of Gloeotrichia echinulata cyanophyceae in lake erken1
Journal of Phycology, 2003Co-Authors: Irene Karlssonelfgren, Emil Rydin, Per Hyenstrand, Kurt PetterssonAbstract:Different parameters in the life cycle of the colony forming cyanobacterium Gloeotrichia echinulata (J.E. Smith) Richter was evaluated in Lake Erken, Sweden. Recruitment of colonies from the sediments and pelagic abundance were measured during 2 years. These data were then used in a model to evaluate and estimate parameters of the life cycle. In our study, recruitment alone only contributed to a small part (<5%) of the maximum G. echinulata abundance that occurred during late summer. However, recruitment from shallow sediments forms the important seed for the pelagic population. Together with measured rates of migration from the sediment, variations in either pelagic colony division rate or pelagic residence time could explain variations in the measured abundance of G. echinulata in situ.
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RECRUITMENT AND PELAGIC GROWTH OF Gloeotrichia ECHINULATA (CYANOPHYCEAE) IN LAKE ERKEN1
Journal of Phycology, 2003Co-Authors: Irene Karlsson-elfgren, Emil Rydin, Per Hyenstrand, Kurt PetterssonAbstract:Different parameters in the life cycle of the colony forming cyanobacterium Gloeotrichia echinulata (J.E. Smith) Richter was evaluated in Lake Erken, Sweden. Recruitment of colonies from the sediments and pelagic abundance were measured during 2 years. These data were then used in a model to evaluate and estimate parameters of the life cycle. In our study, recruitment alone only contributed to a small part (
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Response of the cyanobacterium Gloeotrichia echinulata to iron and boron additions - an experiment from Lake Erken
Freshwater Biology, 2001Co-Authors: Per Hyenstrand, Emil Rydin, Malin Gunnerhed, Jeff Linder, Peter BlomqvistAbstract:1. This study considers whether the availability of iron and boron are important influences on the development of the cyanobacterium Gloeotrichia