Observations on the Seasonal and Spatial Distribution of Testacea (Protozoa: Rhizopoda) in Sphagnum

Heal, O. W.

doi:10.2307/2561

Cited by 90 publications

(40 citation statements)

References 14 publications

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“…This community composition is similar to the hummock fauna described by Heal [26,27] along a fen-bog gradient. The similarities between these surveys are not surprising, and support previous studies in illustrating the cosmopolitan distribution of many peatland testate amoeba morphospecies from the same habitat type [43,64].…”

Section: Testate Amoeba Density and Diversitysupporting

confidence: 80%

“…While the relationship between testate amoebae and DWT and a few other variables such as pH are well documented along broad ecological gradient (e.g., wet pools to dry hummocks, fen to bog) [26,47], much less is known on their finer-scale responses to micro-environmental gradients. Some data suggests that testate amoebae may be highly sensitive even to subtle micro-environmental gradients.…”

Section: Introductionmentioning

confidence: 99%

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Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

et al. 2010

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The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their responses to finerscale gradients, and nothing is known of their possible response to phenolic compounds, which play a key role in carbon storage in peatlands. We studied the vertical (0-3, 3-6, and 6-9 cm sampling depths) micro-distribution patterns of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a "young bog" (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed the relationships between the testate amoeba data and three sets of variables (1) "chemical" (pH, Eh potential, and conductivity), (2) "physical" (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon H′ diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate amoebae, which requires further research.

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Section: Testate Amoeba Density and Diversitysupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

et al. 2010

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“…Species com-monly described as omnivores probably occupy a different trophic level in the microbial network than specific feeders such as bacterivores or predators. Furthermore, many pigmented (photosynthetic) microorganisms are known or suspected to be mixotrophic (i.e., organisms that combine autotrophy and heterotrophy using endosymbiotic zoochlorellae); these include several testate amoeba species such as Hyalosphenia papilio and Archerella flavum [31,32], species that are commonly foundinnorthern Sphagnum peatlands (e.g., [18,[33][34][35][36]). The mixotrophic life trait has significant functional and physi-ological implications [10,37,38] and should theoretically translate into distinct isotopic ratios.…”

Section: Introductionmentioning

confidence: 99%

To What Extent Do Food Preferences Explain the Trophic Position of Heterotrophic and Mixotrophic Microbial Consumers in a Sphagnum Peatland?

et al. 2013

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Although microorganisms are the primary drivers of biogeochemical cycles, the structure and functioning of microbial food webs are poorly studied. This is the case in Sphagnum peatlands, where microbial communities play a key role in the global carbon cycle. Here, we explored the structure of the microbial food web from a Sphagnum peatland by analyzing (1) the density and biomass of different microbial functional groups, (2) the natural stable isotope (δ 13 C and δ 15 N) signatures of key microbial consumers (testate amoebae), and (3) the digestive vacuole contents of Hyalosphenia papilio, the dominant testate amoeba species in our system. Our results showed that the feeding type of testate amoeba species (bacterivory, algivory, or both) translates into their trophic position as assessed by isotopic signatures. Our study further demonstrates, for H. papilio, the energetic benefits of mixotrophy when the density of its preferential prey is low. Overall, our results show that testate amoebae occupy different trophic levels within the microbial food web, depending on their feeding behavior, the density of their food resources, and their metabolism (i.e., mixotrophy vs. heterotrophy). Combined analyses of predation, community structure, and stable isotopes now allow the structure of microbial food webs to be more completely described, which should lead to improved models of microbial community function.

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“…1). Indeed testate amoeba density and community structure were previously shown to respond to soil moisture fluctuations [25,29,[46][47][48].…”

Section: Testate Amoeba Community Composition Species Richness and Dmentioning

confidence: 99%

Can soil testate amoebae be used for estimating the time since death? A field experiment in a deciduous forest

Szelecz

Fournier

Seppey

et al. 2014

Forensic Science International

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Observations on the Seasonal and Spatial Distribution of Testacea (Protozoa: Rhizopoda) in Sphagnum

Cited by 90 publications

References 14 publications

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

To What Extent Do Food Preferences Explain the Trophic Position of Heterotrophic and Mixotrophic Microbial Consumers in a Sphagnum Peatland?

Can soil testate amoebae be used for estimating the time since death? A field experiment in a deciduous forest

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