Particle capture by <i>Favella</i> sp. (Ciliata, Tintinnina)

Stoecker, Diane K.; Gallager, Scott M.; Langdon, Chris; Davis, Linda H.

doi:10.1093/plankt/17.5.1105

Cited by 36 publications

(35 citation statements)

References 32 publications

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“…Differential prey uptake has been observed in ciliates (Verity 1991), and Favella sp. have been shown to reject H. akashiwo cells (Taniguchi & Takeda 1988, Stoecker et al 1995, signifying selective prey consumption among grazers. If ingestion of H. akashiwo rises only when it is the sole prey source, and ingestion plays a role in toxicity, then the presence of alternative prey would reduce this toxicity by allowing the grazer to shift its ingestion from the raphidophyte to a more beneficial prey source.…”

Section: Dual-prey Experimentsmentioning

confidence: 99%

Growth and grazing of microzooplankton in response to the harmful alga Heterosigma akashiwo in prey mixtures

Graham¹,

Strom²

2010

Aquat. Microb. Ecol.

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Microzooplankton grazers may play a role in regulating blooms of the ichthyotoxic alga Heterosigma akashiwo. This study tested the effects of H. akashiwo, when part of a mixed-prey assemblage, on the growth and feeding of microzooplankton. Laboratory cultures of 3 ciliates, Favella sp., Metacylis sp., and Strombidinopsis acuminatum, were exposed to reciprocal concentrations of H. akashiwo and a non-toxic prey, at saturating prey concentrations. Heterosigma akashiwo was toxic to Favella sp. and Metacylis sp. when H. akashiwo was the sole prey species; however, this toxicity was eliminated in the mixed-prey treatments, likely because of avoidance of H. akashiwo and selective feeding on non-toxic prey. In contrast, the growth rate of S. acuminatum was unaffected by H. akashiwo. Both Favella sp. and S. acuminatum ingested H. akashiwo but selected against the alga when other prey was available. In addition, natural planktonic communities, collected from East Sound, Orcas Island, northern Puget Sound, in September and October 2007, were exposed to bloomlevel concentrations of H. akashiwo. Abundances of the major microzooplankton types, primarily ciliates and Gyrodinium/Gymnodinium dinoflagellates, were unaffected by H. akashiwo, although slight changes in grazer size structure did occur. Heterosigma akashiwo was harmful to the smallest grazers, mainly aloricate ciliates and small Gyrodinium/Gymnodinium dinoflagellates, and beneficial to larger Gyrodinium/Gymnodinium dinoflagellates that were able to ingest and grow on the alga. The alga was not consumed by the majority of grazers. Preferential feeding on alternate prey reduces toxic effects of H. akashiwo on microzooplankton. Avoidance of H. akashiwo by a major group of grazers would promote bloom formation by reducing H. akashiwo mortality and focusing community grazing pressure on potential competitor species.

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Section: Dual-prey Experimentsmentioning

confidence: 99%

Growth and grazing of microzooplankton in response to the harmful alga Heterosigma akashiwo in prey mixtures

Graham¹,

Strom²

2010

Aquat. Microb. Ecol.

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“…In addition, bacterivores increased relative to algivores during summer as re-oligotrophication progressed: From July to • September the contribution of Cluster 7, which was largely made up of small scuticociliates known to feed mainly on picoplankton (2imek et al 1994, 1995), increased from an average of 0.4% from 1987 to 1993 to 3% in the 5 yr thereafter. Tintinnids, which graze on both auto-and heterotrophs in the nano-to micro-size range (Stoecker & Evans 1985, Stoecker et al 1995, did the opposite, decreasing from an average of 16% in the period from 1987 to 1994, then 3% thereafter.• The decline in ciliate biomass in July with TP mix (Fig. 5a) is presumably directly related to the concomitant decrease in chlorophyll concentrations and primary production, rather than to enlarged topdown control, because daphnid biomass declined strongly in July during the most oligotrophic years.…”

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confidence: 99%

Ciliate dynamics in response to changing biotic and abiotic conditions in a large, deep lake (Lake Constance)

Gaedke¹,

Wickham²

2004

Aquat. Microb. Ecol.

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From 1987 to 1998, ciliates and their prey and predator communities in Lake Constance (which is large, deep and meso-eutrophic) were intensively studied as the lake underwent reoligotrophication. Ciliate biomass exhibited the bimodal seasonal distribution typical for mesoeutrophic lakes, with high biomass in spring and summer and low biomass in winter and during the clear-water phase. Cluster analysis produced 9 groups of temporally co-occurring ciliate morphotypes with potentially similar ecological characteristics. The clusters exhibited a larger seasonality than found in the size distribution, showing that size alone failed to capture some ciliate seasonal dynamics. Ciliate biomass declined by approx. 30% during the 12 yr of study, i.e. considerably less than daphnids (and total phosphorus). This yielded a significant increase in the ratio between summer ciliate and daphnid biomass as re-oligotrophication progressed, in contrast to previous studies. Few indications for a mechanistic link between phosphorus concentrations (which declined 3-fold during the study period) and ciliate biomass or community composition via group-specific food concentrations were found. The relative contribution of 3 of the 9 clusters changed as re-oligotrophication progressed. Ciliate size distribution was related to re-oligotrophication and daphnid biomass in summer. The smallest and largest ciliates gained importance when daphnids decreased, whereas the biomass of large ciliates declined. Generally, summer daphnid biomass had a greater predictive power for attributes of the ciliate community than the other factors studied (phosphorus, prey biomass, copepod biomass). The extent of bottom-up and top-down control of ciliates appeared to be time-and groupspecific. Overall, the ciliate community exhibited remarkably recurrent seasonal patterns, despite major alternations in abiotic and biotic conditions. KEY WORDS: Ciliates · Long-term observations · Bottom-up control · Top-down control · Eutrophication · Daphnids · Copepods Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 34: [247][248][249][250][251][252][253][254][255][256][257][258][259][260][261] 2004 ton) may be closely linked and subject to external forcing by climate and nutrient changes.In Lake Constance, which is large, deep and mesoeutrophic, intensive investigations of the planktonic ciliate community revealed recurrent seasonal patterns in ciliate abundances and taxonomic community composition from 1987to 1989(Müller 1989. Biomass peaks developed in early spring immediately after the onset of phytoplankton growth, and in summer/autumn after the clear-water phase, during which time ciliate biomass was low. In spring, small algivorous ciliates such as Balanion planctonicum were typical, while the summer community was characterized by a somewhat higher variability in taxonomical composition and feeding types (Müller 1989. Laboratory studies provided insight into ciliate ingestion and production rates, preferred algal...

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“…It is known that Favella sp. will reject captured H. akashiwo cells (Taniguchi and Takeda 1988;Stoecker et al 1995), and will discriminate against H. akashiwo in prey mixtures (Graham and Strom 2010). However, when H. akashiwo is ingested by Favella sp., mortality of the ciliate rapidly follows (Verity and Stoecker 1982;Clough and Strom 2005;Graham and Strom 2010).…”

Section: Discussionmentioning

confidence: 99%

Avoidance, movement, and mortality: The interactions between a protistan grazer and Heterosigma akashiwo, a harmful algal bloom species

Harvey

Menden‐Deuer

2011

Limnology & Oceanography

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A reduction in predator-induced grazing pressure may be a mechanism that facilitates the formation and persistence of harmful algal blooms. Here, the hypothesis was tested that the heterotrophic ciliate Favella ehrenbergii would use avoidance behaviors to reduce encounters with the toxic bloom-forming alga, Heterosigma akashiwo. Using video and image-analysis, population distributions and three-dimensional movements of F. ehrenbergii and H. akashiwo were quantified in triplicate, hourly for 11 h, at nine horizons in a 1-liter experimental column. The salinity structure in the column was manipulated to include a halocline, resulting in layer formation by H. akashiwo. The ciliate's vertical distributions were restricted to high-salinity waters below the halocline, while H. akashiwo was broadly halo-tolerant and could occupy the whole water column. When observed together, F. ehrenbergii did not avoid layers of H. akashiwo. In the presence of H. akashiwo, F. ehrenbergii mortality rates were higher than in either no prey or beneficial prey controls. Swimming behaviors of F. ehrenbergii were erratic, in response to H. akashiwo, compared to aggregative movements in response to beneficial prey, indicating either a behavioral response or the effect of H. akashiwo toxicity on the ciliate. The inability of F. ehrenbergii to avoid H. akashiwo enhanced predator mortality and may contribute to the survival of the harmful algal bloom species, ultimately promoting the formation of H. akashiwo harmful algal blooms.

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Particle capture by Favella sp. (Ciliata, Tintinnina)

Cited by 36 publications

References 32 publications

Growth and grazing of microzooplankton in response to the harmful alga Heterosigma akashiwo in prey mixtures

Growth and grazing of microzooplankton in response to the harmful alga Heterosigma akashiwo in prey mixtures

Ciliate dynamics in response to changing biotic and abiotic conditions in a large, deep lake (Lake Constance)

Avoidance, movement, and mortality: The interactions between a protistan grazer and Heterosigma akashiwo, a harmful algal bloom species

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