Journal articles: 'Testate amoebae'

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Liu, Bing, Robert K. Booth, Jaime Escobar, Zhiqiang Wei, Broxton W. Bird, Andres Pardo, Jason H. Curtis, and Jun Ouyang. "Ecology and paleoenvironmental application of testate amoebae in peatlands of the high-elevation Colombian páramo." Quaternary Research 92, no. 1 (February 18, 2019): 14–32. http://dx.doi.org/10.1017/qua.2018.143.

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AbstractWe investigated the ecology and paleoecology of testate amoebae in peatlands of the Colombian páramo to assess the use of testate amoebae as paleoenvironmental indicators. Objectives were to (1) identify environmental controls on testate amoebae, (2) develop transfer functions for paleoenvironmental inference, and (3) examine testate amoebae in a Holocene peat core and compare our findings with other proxy records. Results from 96 modern samples indicate that testate amoebae are sensitive to pH and surface moisture, and cross-validation of transfer functions indicates potential for paleoenvironmental applications. Testate amoebae from the Triunfo Peatland in the Central Cordillera provided a proxy record of pH and water-table depth for the late Holocene, and inferred changes were correlated with peat C/N measurements during most of the record. Comparison with a lake-level reconstruction suggests that at least the major testate amoeba–inferred changes were driven by climate. Our work indicates that testate amoebae are useful paleoenvironmental indicators in high-elevation tropical peatlands.

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Booth, Robert, and Jennifer Zygmunt. "Testate Amoebae as Paleoclimatic Proxies in Rocky Mountain Peatlands: A Case Study in the Greater Yellowstone Ecosystem." UW National Parks Service Research Station Annual Reports 26 (January 1, 2002): 85–96. http://dx.doi.org/10.13001/uwnpsrc.2002.3513.

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We investigated the potential of testate amoebae (Protozoa: Rhizopoda) for reconstructing past climate changes in the Rocky Mountain region. Our specific objectives were to determine environmental controls on modem testate amoeba distribution in Sphagnum-dominated peatlands of the region, reconstruct past temporal changes in testate amoebae from a Sphagnum-dominated peatland in southwestern Yellowstone National Park, and assess relationships between climate variability and testate amoebae for the past century. Our results indicate that substrate moisture is the dominant control on modem testate amoeba distribution in the region, consistent with studies from other regions. Temporal changes in testate amoebae reconstructed from a floating peat mat in the Greater Yellowstone Ecosystem show considerable variability during the past several hundred years, and variability during the past century was correlated with the instrumental record of drought at decadal timescales. The patterns suggest that sensitive paleoclimatic reconstructions are possible from floating mats in the region, and perhaps elsewhere. Testate amoebae from peatlands in the Rocky Mountains show great potential for reconstructing past climate variability, corroborating and extending records inferred from other proxies.

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Baković, Najla, Ferry Siemensma, Sanja Puljas, Robert Baković, Roman Ozimec, Ana Ostojić, and Zrinka Mesić. "First data on testate amoebae associated with the endemic cave bivalve Congeria jalzici Morton & Bilandžija, 2013 with a description of Psammonobiotus dinarica sp. nov." Subterranean Biology 45 (February 21, 2023): 53–74. http://dx.doi.org/10.3897/subtbiol.45.97105.

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Testate amoebae are phylogenetically a very diverse group of eukaryotic microorganisms. They can be found in marine and freshwater habitats and in soil. Some of these single-celled organisms inhabit both surface and cave habitats, but their diversity in caves has barely been explored. Recent studies in the Dinaric region imply that testate amoebae in caves show a high diversity. The aim of this study was to identify the alpha diversity of testate amoebae in the Lika region (Dinaric karst, Croatia) and to compare the habitats of different caves based on testate amoebae assemblages. In eight caves we found more than 40 testate amoebae taxa, including a new testate amoeba species, Psammonobiotus dinaricasp. nov. The greatest diversity of testate amoebae was found in Markov ponor (27 taxa). The Bray-Curtis Similarity Index showed that testate amoebae assemblages in caves inhabited by the endemic and endangered cave bivalve Congeria jalzici (Markov ponor, Dankov ponor and Dražice ponor) differ from caves not inhabited by this species. This differentiation is attributed to the impact of the sinking Lika river, which occasionally completely submerges these caves, creating specific habitats for eukaryotic microorganisms. This study contributes to our understanding of the diversity, biogeography and ecology of testate amoebae in caves, as well as providing further insight into the conditions that sustain populations of C. jalzici.

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Marcisz, Katarzyna, Krzysztof Buczek, Mariusz Gałka, Włodzimierz Margielewski, Matthieu Mulot, and Piotr Kołaczek. "Past testate amoeba communities in landslide mountain fens (Polish Carpathians): The relationship between shell types and sediment." Holocene 31, no. 6 (February 18, 2021): 954–65. http://dx.doi.org/10.1177/0959683621994647.

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Landslide mountain fens formed in landslide depressions are dynamic environments as their development is disturbed by a number of factors, for example, landslides, slopewash, and surface run-off. These processes lead to the accumulation of mineral material and wood in peat. Disturbed peatlands are interesting archives of past environmental changes, but they may be challenging for providing biotic proxy-based quantitative reconstructions. Here we investigate long-term changes in testate amoeba communities from two landslide mountain fens – so far an overlooked habitat for testate amoeba investigations. Our results show that abundances of testate amoebae are extremely low in this type of peatlands, therefore not suitable for providing quantitative depth-to-water table reconstructions. However, frequent shifts of dominant testate amoeba species reflect dynamic lithological situation of the studied fens. We observed that high and stable mineral matter input into the peatlands was associated with high abundances of species producing agglutinated (xenosomic) as well as idiosomic shells which prevailed in the testate amoeba communities in both analyzed profiles. This is the first study that explores testate amoebae of landslide mountain fens in such detail, providing novel information about microbial communities of these ecosystems.

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Zagumyonnaya, O. N., D. A. Philippov, D. G. Zagumyonnyi, A. A. Komarov, A. N. Tsyganov, and D. V. Tikhonenkov. "CHANGES IN TESTATE AMOEBA ASSEMBLAGES IN A SERIES OF DIFFERENT-TYPE AQUATIC AND TERRESTRIAL HABITATS OF WETLAND AND FOREST ECOSYSTEMS." Зоологический журнал 102, no. 1 (January 1, 2023): 3–21. http://dx.doi.org/10.31857/s0044513423010117.

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Patterns of changes in the species richness, abundance, community structure, and biomass of testate amoebae were studied in a series of different-type aquatic and terrestrial habitats along an interlake transect in the Tyumen Region. Altogether, 112 species and forms of testate amoebae, including subspecies, were identified. Micrographs of all species detected are given. The species Conicocassis pontiguasiformis (Beyens et al., 1986) Nasser and Anderson, 2015, previously described as an arctic endemic, was found in the south of Western Siberia for the first time. The species richness of testate amoeba assemblages is maximal in the periphyton. The highest values of species numbers and biomass were detected in the bottom detritus of the coastal part of a swamp lake. Testate amoeba assemblages in various habitats along the transect are divided into aquatic and terrestrial, according to the results of cluster and principal component analyses. The species composition of testate amoeba assemblages depended on substrate wetness, as well as the type of vegetation. The dominants in relative biomass were identified for aquatic, forest, and well-lit Sphagnum habitats.

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Kornecki, Krystyna M., Matthew S. Schuler, Miraim E. Katz, Rick A. Relyea, Francine M. G. McCarthy, Morgan F. Schaller, David P. Gillikin, et al. "The Canary in the Coal Mine: Testate Amoebae Record Anthropogenic Impacts in Sediments of Oligotrophic Lake George, NY, USA." Journal of Foraminiferal Research 50, no. 2 (April 1, 2020): 128–40. http://dx.doi.org/10.2113/gsjfr.50.2.128.

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ABSTRACT Lake George (NY) is surrounded by Forever Wild Forest in the Adirondack Park and has a Class AA Special water quality rating, yet lake monitoring has revealed increasing anthropogenic impacts from salt and nutrient loading over the past 30 years. To reconstruct anthropogenic influence on the lake (e.g., salt loading, eutrophication, climate warming), we characterized modern stable isotopes and testate amoeba and diatom assemblages in surface sediments from 33 lake-wide sites and compared their variability to 36 years of water-quality data. Linear regression analyses support testate amoebae as rapid responders and recorders of environmental change because taxa are strongly correlated with percent change of important water quality parameters. Our assessment indicates that: 1) Netzelia gramen is associated with aquatic plants and filamentous algae, making them a valuable aquatic plant/alga indicator, which is supported by the co-occurrence of the diatom Cocconeis spp.; 2) difflugids are generally good indicators of eutrophication, except for Difflugia protaeiformis; and 3) seasonal differences in water quality trends are reflected in the fossil record on decadal time scales. We show that testate amoebae are highly sensitive to small environmental changes in an oligotrophic lake and exhibit established relationships from eutrophic and mesotrophic lakes as well as new, likely oligotrophic-specific correlations. Correlation coefficients of water quality variables and strains within a species also illustrate gradational relationships, suggesting testate amoebae exhibit ecophenotypic plasticity. Diatom and testate amoeba assemblages categorize modern lakebed sites into four subgroups: 1) benthic macrophyte; 2) high nutrient; 3) high alkalinity; and 4) salt loading assemblages.

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Sysoev, Vlad V., Andrey N. Tsyganov, Fedor Y. Reshetnikov, and Yuri A. Mazei. "The Effects of Sampling Depth on Benthic Testate Amoeba Assemblages in Freshwater Lakes: A Case Study in Lake Valdayskoe (the East European Plain)." Diversity 14, no. 11 (November 12, 2022): 974. http://dx.doi.org/10.3390/d14110974.

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Testate amoebae are widely used as proxies in paleoecological reconstructions of lacustrine environments; however, our knowledge on their distribution along depth gradients are limited. This study investigates the distribution of benthic testate amoebae along a sampling depth gradient (0 to 57 m) and related environmental characteristics in Lake Valdayskoe, Russia. In total, 101 species belonging to twenty-one genera were identified. Four types of testate amoeba assemblages (littoral, sublittoral, bottom slope and profundal) were distinguished that corresponded well to the bottom zones of the lake. The results of redundancy analysis indicated that sampling depth, temperature, pH and bottom inclination significantly explained 40.2% of the total variance in the species composition. Temperature and sampling depth had the largest individual contributions of 19.2 and 7.4% (p < 0.001), respectively. The minimal values of species diversity were observed on the littoral and at the lower boundary of the thermocline. We estimated depth optima and ranges for the species with high occurrences and distinguish stenobathic and eurybathic species. These data might improve the interpretations of paleoecological records of subfossil testate amoeba assemblages in lacustrine surface sediments and serve as basis for the development of a transfer function for reconstruction of lake depths.

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Tsyganov, Andrey, Elena Malysheva, Yuri Mazei, K. Hapsari, Hermann Behling, Supiandi Sabiham, Siria Biagioni, and Valentyna Krashevska. "Species and Trait-Based Reconstructions of the Hydrological Regime in a Tropical Peatland (Central Sumatra, Indonesia) during the Holocene Using Testate Amoebae." Diversity 14, no. 12 (December 1, 2022): 1058. http://dx.doi.org/10.3390/d14121058.

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Paleoecological reconstructions of hydrological regimes in tropical peatlands during the Holocene are important for the estimation of their responses to changing environments. However, the application of some widely used proxies, such as testate amoebae, is hampered by poor knowledge of their morphology and ecological preferences in the region. The aim of this study is to describe the morphospecies composition of sub-fossil testate amoebae in deposits of a tropical peatland in Central Sumatra (Indonesia) during the Holocene and reconstruct the hydrological regime using morphospecies- and functional-trait-based approaches. In total, 48 testate amoeba morphospecies were observed. Based on morphospecies composition, we distinguished three main periods of peatland development (13,400–8000, 8000–2000, 2000 cal yr BP–present). The application of the morphospecies-based transfer function provided a more reliable reconstruction of the water regime in comparison to the functional trait-based one. The weak performance of the latter might be related to the poor preservation of shells and the greater variation in the functional traits in sub-fossil communities as compared to the training set and linear modeling approach. These results call for future studies on the functional and morphospecies composition of testate amoebae in a wider range of tropical peatlands to improve the quality of hydrological reconstructions.

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Golemansky, Vassil, and Rositsa Davidova. "Biodiversity, Distribution and Ecology of Testate Amoebae (Arcellinida and Euglyphida) from the Bulgarian Black Sea Coast and the related brackish lakes. A Synthesis." Acta Scientifica Naturalis 6, no. 2 (December 1, 2019): 14–39. http://dx.doi.org/10.2478/asn-2019-0016.

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Abstract The studies on the marine and freshwater testate amoebae of the Bulgarian Black Sea littoral and some related coastal brackish lakes are briefly reviewed. So far, a total of 184 species and subspecies of testate amoebae from 18 families and 45 genera from orders of Arcellinida and Euglyphida were published in national and international journals. The underground waters of the Bulgarian marine sand supralittoral are better studied than the related continental lakes. A total of about 45 species of marine interstitial testate amoebae are known, so far, and a big part of them were for the first time described from the Black Sea littoral. It’s interesting to note the presence in the marine underground waters of the Black Sea littoral of many freshwater testate amoebae also, considered by us as eurybionts. That is due of the low and variable salinity of the littoral Black Sea waters during the year. The presence of some psammobiotic testate amoebae as Psammonobiotus lineare and Corythionella georgiana in some related brackish lakes is also of ecological interest. The general conclusion of the present synthesis is that the testate amoebae fauna of the Bulgarian Black Sea coast and the related with it many brackish and freshwater littoral lakes is few known yet and need more active researches.

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Misailidis, Maria Laura, Nicolás Misailidis Strikis, Rubens Cesar Figueira, Renato Campello Cordeiro, Pedro Carlos Strikis, Leonardo Antonio Pregnolato, and Wânia Duleba. "TESTATEAMOEBAE AS BIO-INDICATORS OF CONTAMINATION BY TRACE ELEMENTS IN THE RESERVOIR OF SALTO GRANDE AMERICANA-SP, BRAZIL." Journal of Sedimentary Environments 2, no. 4 (January 31, 2018): 183–200. http://dx.doi.org/10.12957/jse.2017.32586.

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This work aims to evaluate the degree of sediment contamination and the response of Testate amoebae populations through a sediment core taken from the Salto Grande Reservoir (RSG), situated in Americana, in São Paulo State (SP), Brazil. It is based on the analysis of the trace elements geochemistry (by ICP-OES) and Testate amoebae data (by stereomicroscopic morphometric analysis). The indices of homogeneity and richness (Simpson 1-D and Margalef) were calculated. Sediment contamination was evaluated according to VGQS (TEL and PEL). The results evidenced that the sediments of Facies 3 are highly contaminated since the beginning of RSG filling. Contamination caused significant decline of Testate amoebae populations dimension and diversity. In sedimentary facies with lower concentrations of trace elements diversity and size of Testate amoebae populations are higher and are composed of different species. The results of this work indicate that Testate amoebae populations showed differentiated responses to different environmental conditions. So, these amoeboid protists can be considered good indicators of pollution caused by trace elements in fresh water aquatic environments.

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Chertoprud, Elena S., Anna A. Novichkova, Andrey N. Tsyganov, Lada V. Vorobjeva, Anton S. Esaulov, Sergey V. Krylenko, and Yuri A. Mazei. "Species Diversity and Driving Factors of Benthic and Zooplanktonic Assemblages at Different Stages of Thermokarst Lake Development: A Case Study in the Lena River Delta (Middle Siberia)." Diversity 15, no. 4 (April 2, 2023): 511. http://dx.doi.org/10.3390/d15040511.

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Global climate change might result in permafrost thaw and the formation of thermokarst landscapes that release long-term carbon stocks as greenhouse into the atmosphere, thereby initiating a positive climate feedback. These processes are mediated by biological activity, including by microbes, vascular plants and animals, whereas the role of invertebrates in thermokarst ecosystems remains poorly understood. We investigated the diversity and assemblage structures of zooplankton (mainly Copepoda, Cladocera), microbenthos (testate amoebae) and meio- (Copepoda and Cladocera) and macrozoobenthos (mollusks, crustaceans, insects and annelids) from a range of water bodies representing different stages of thermokarst lake formation in the southern part of the Lena River Delta (Central Siberia). Altogether, 206 species of testate amoeba, mollusk, crustacean, insect and annelid taxa were identified. A total of 60 species of macrozoobenthos (mainly insects) and 62 species of testate amoebae were detected in the water bodies of the Lena River Delta for the first time. The species richness of zooplankton and meio- and macrozoobenthos was greater in the large thermokarst lakes than in the polygonal ponds due to the freezing of the latter in the winter. In contrast, the species richness of protists was higher in the polygonal ponds, which was related to the habitat preferences of testate amoebae. Fish grazing strongly affected the macrobenthos assemblages but not the smaller-sized organisms. Water acidity and temperature were the main environmental drivers of the assemblage structure of testate amoeba and microcrustacean. The species structure of the macroinvertebrate assemblages was significantly explained by water acidity, permafrost depth and size of the water area. It means that small size organisms with their short generation times are sensitive to more dynamic factors such as temperature and may serve as indicators of ecosystem changes due to global climate warming. In contrast, large size organisms are affected by driven factors that appear during thermokarst lakes formation and permafrost degradation.

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L., Bindu. "New Records of Testate Amoebae in Shenthuriney Wildlife Sanctuary, Kerala, India: Insights into Microbial Biodiversity." Journal of Scientific Research and Reports 29, no. 9 (September 14, 2023): 55–63. http://dx.doi.org/10.9734/jsrr/2023/v29i91784.

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This report summarizes the results hitherto achieved in the study of moss inhabitant testate amoebae in Shenthuriney WLS, part of Western Ghats, Kerala. This is the first study on this important protozoan group in the sanctuary to document the testate fauna.The study reveals the novel records of 28 species of testate amoebae span over 6 families and 9 genera from Shenthuriney WLS, Kerala.

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Mitchell, Edward A. D., Richard J. Payne, Willem O. van der Knaap, Łukasz Lamentowicz, Maciej Gąbka, and Mariusz Lamentowicz. "The performance of single- and multi-proxy transfer functions (testate amoebae, bryophytes, vascular plants) for reconstructing mire surface wetness and pH." Quaternary Research 79, no. 1 (January 2013): 6–13. http://dx.doi.org/10.1016/j.yqres.2012.08.004.

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AbstractPeatlands are widely exploited archives of paleoenvironmental change. We developed and compared multiple transfer functions to infer peatland depth to the water table (DWT) and pH based on testate amoeba (percentages, or presence/absence), bryophyte presence/absence, and vascular plant presence/absence data from sub-alpine peatlands in the SE Swiss Alps in order to 1) compare the performance of single-proxy vs. multi-proxy models and 2) assess the performance of presence/absence models. Bootstrapping cross-validation showing the best performing single-proxy transfer functions for both DWT and pH were those based on bryophytes. The best performing transfer functions overall for DWT were those based on combined testate amoebae percentages, bryophytes and vascular plants; and for pH, those based on testate amoebae and bryophytes. The comparison of DWT and pH inferred from testate amoeba percentages and presence/absence data showed similar general patterns but differences in the magnitude and timing of some shifts. These results show new directions for paleoenvironmental research, 1) suggesting that it is possible to build good-performing transfer functions using presence/absence data, although with some loss of accuracy, and 2) supporting the idea that multi-proxy inference models may improve paleoecological reconstruction. The performance of multi-proxy and single-proxy transfer functions should be further compared in paleoecological data.

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Payne, Richard J., Mariusz Lamentowicz, W. O. van der Knaap, Jacqueline F. N. van Leeuwen, Edward A. D. Mitchell, and Yuri Mazei. "Testate amoebae in pollen slides." Review of Palaeobotany and Palynology 173 (April 2012): 68–79. http://dx.doi.org/10.1016/j.revpalbo.2011.09.006.

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Viana Souza Rocha, Cínthya, Matheus Santos dos Anjos, Deivson Araújo Brandão, Caio Ceza da Silva Nunes, Mariane Amorim Rocha, Patricia Belini Nishiyama, Ricardo Evangelista Fraga, Patricia Maria Mitsuka, and Márcio Borba da Silva. "Testate amoebae (Arcellinida and Euglyphida) from Pantanal dos Marimbús, Chapada Diamantina, Bahia state, Brazil, including new occurrences." Check List 17, no. 5 (September 3, 2021): 1205–19. http://dx.doi.org/10.15560/17.5.1205.

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Testate amoebae are single-celled protists whose protoplasm is contained within a carapace composed of gelatinous to imbricated chitinous plates having variable chemical compositions. We inventoried the testate amoebae community present in the plankton and periphyton of the Pantanal dos Marimbus swamp in Bahia state, Brazil. Sixty-five samples of plankton and periphyton were analyzed during May and September/2014 and April/2015. We identified 65 taxa of testate amoebae distributed in eight families, 15 genera, 45 species, and 16 varieties. The most representative families were Arcellidae, Centropyxidae, and Difflugiidae, corresponding to 24.6%, 19.7% and 14.8% of the taxa respectively. The periphyton had greater richness (59 taxa) than the plankton (39 taxa). Of the taxa found, 15 represent new records for Bahia and 14 for northeastern Brazil. The Marimbus Pantanal swamp showed an expressive richness of testate amoebae, and our data increases the number of species of these organisms known to Bahia and northeastern Brazil, where work with those organisms is still scarce.

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Porter, Susannah M., Ralf Meisterfeld, and Andrew H. Knoll. "Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon: A classification guided by modern testate amoebae." Journal of Paleontology 77, no. 3 (May 2003): 409–29. http://dx.doi.org/10.1017/s0022336000044140.

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Vase-shaped microfossil (VSM) assemblages from early diagenetic carbonate nodules in >742 ± 6 Ma black shales of the Chuar Group, Grand Canyon, provide evidence for affinities with testate amoebae. Not only are VSMs exceptionally preserved in Chuar rocks, they exhibit a much higher degree of morphological diversity than was previously known. Using the taxonomy of modern testate amoebae as a guide, nine new species and eight new genera of VSMs are described, augmenting the eight species and two genera already recognized. Taxa described here areMelanocyrillium hexodiademaBloeser, 1985,Trigonocyrillium horodyskii(Bloeser, 1985) n. comb.,T. fimbriatum(Bloeser, 1985) n. comb.,Cycliocyrillium simplexn. sp.,C. torquatan. sp.,Bonniea dacrucharesn. sp.,B. pytinaian. sp.,Trachycyrillium pudensn. sp.,Palaeoarcella athanatan. sp.,Hemisphaeriella ornatan. sp.,Bombycion micronn. sp., andMelicerion poikilonn. sp. All of the test characters observed in VSM taxa (e.g., collars; indentations; hexagonal symmetry; lobed, triangular or invaginated apertures; curved necks) occur in modern testate amoeban taxa, though not always in the same combinations. Some VSM species have characters found today in diverse extant taxa, making it difficult to assess their relationships. A few species, however, have character combinations that closely approximate those found in specific genera of both lobose and filose testate amoebae, suggesting that at least stem group, and possibly crown group, representatives of these taxa were present ∼742 Ma.These fossils indicate that ecosystems were diverse and complex, that eukaryotic biomineralization had already evolved, and that the last common ancestor of animals+fungi had already appeared by ∼750 Ma.

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Загумённая, О. Н. "Testate amoebae of the natural monument bog “Klyukvennoye-2” (Usman pine forest, Voronezh Oblast, Russia)." Ecosystem Transformation, no. 2(25) (May 30, 2024): 19–31. http://dx.doi.org/10.23859/estr-221110.

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В работе впервые рассматриваются результаты изучения видового состава сооб- ществ раковинных амеб из разнотипных микробиотопов, отличающихся по степени обводнен- ности и составу субстрата переходного болота Клюквенное-2 (ООПТ) Усманского бора. Выяв- лено 72 вида раковинных амеб. Наиболее богатыми по числу видов и количественному обилию были мезофильные сообщества раковинных амеб, населяющие промежуточные местообитания между моховыми и водными микробиотопами. Сообщество раковинных амеб, населяющих су- хие сфагновые кочки, отличалось самыми низкими показателями. Среди всех выявленных видов Arcella gibbosa имела максимальное количественное обилие. This paper was the first to present the results of investigations of species composition of testate amoebae from different microbiotopes with regard to watering and a substrate type of the protected natural area “ bog Klyukvennoye-2” of Usman Pine Forest. A total of 72 species of testate amoebae were identified. Mesophilic communities of testate amoebae dwelling in the intermediate habitats between moss and aquatic microbiotopes were the richest in terms of species number and abundance. These indicators for the testate amoebae community inhabiting dry sphagnum tussocks turned out to be the least. Arcella gibbosa had the highest abundance among all identified species.

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Baković, Najla, Ferry J. Siemensma, Robert Baković, and Josip Rubinić. "Testate Amoebae in Karst Caves of the Dinaric Arc (South-Eastern Europe) with a Description of Centropyxis bipilata sp. nov." Acta Protozoologica 58, no. 4 (2019): 201–15. http://dx.doi.org/10.4467/16890027ap.19.018.12020.

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Karst freshwater caves are subterranean habitats characterized by the constant absence of light and relatively small variations of temperature and air humidity. They are mostly food deprived environments, with the exception if large bat colonies are present or if they are intensively supplied with organic matter by sinking rivers. Even though these habitats are often described as harsh, they have enabled the evolution of highly specialized and often endemic animals. The cave eukaryotic micro-organisms, on the other hand, are scarcely researched. The results of research of testate amoebae in the caves of the Dinaric arc detected 23 species, 12 of which were first found in caves. Also, a description of Centropyxis bipilata sp. nov. is presented. This species is clearly distinguished from other described species based on shell size, the presence of two struts and the usually dark ring around the aperture. Testate amoebae were registered on aquatic and terrestrial cave sediments and transitional habitats (like hygropetric and wet walls). The most frequent species within the samples were: Trinema lineare, Cryptodifflugia oviformis and Centropyxis bipilata sp. nov. Maximum diversity of testate amoebae was registered in Ponor Kovači with twenty species. In 24.4 % of the investigated samples microphototrophs were found, implying good surface-subsurface connectivity that could also affect testate amoebae diversity. This research showed that caves are underestimated habitats that can provide us with new data about the testate amoebae biogeography and diversity.

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Carballeira, Rafael, and Xabier Pontevedra-Pombal. "Diversity of Testate Amoebae as an Indicator of the Conservation Status of Peatlands in Southwest Europe." Diversity 13, no. 6 (June 15, 2021): 269. http://dx.doi.org/10.3390/d13060269.

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Testate amoebae are one of the most studied groups of microorganisms in Sphagnum peatland ecosystems and, therefore, one of the most reliable bioindicators of their ecological status. Peatland ecosystems are supported by a delicate biogeochemical balance that leads to the formation of peat, one of the main sinks of C, as a result of soil–atmosphere interaction, but currently they are one of the most threatened wetland types at their southern distribution limit. In the European continent, where climatic conditions limit peat formation, they have endured significant anthropic pressure for centuries, and the risk of loss of biodiversity linked to these ecosystems is critical. In addition, peatlands are poorly known ecosystems in the Iberian Peninsula compared with other wetlands; therefore, we have studied the chemical parameters of water and the diversity patterns of testate amoebae in the western Iberian Peninsula to better understand the current status of these ecosystems. The analysis of testate amoeba communities showed an inverse relationship between the diversity and conservation status of these peatlands, both in relation to chemical parameters (i.e., pH, electrical conductivity, phosphates) and to the proportion of anthropized area, with a marked geographical pattern in the degree of anthropogenic disturbance.

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Payne, Richard J., Edward A. D. Mitchell, Hung Nguyen-Viet, and Daniel Gilbert. "Can pollution bias peatland paleoclimate reconstruction?" Quaternary Research 78, no. 2 (May 31, 2012): 170–73. http://dx.doi.org/10.1016/j.yqres.2012.05.004.

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AbstractPeatland testate amoebae are widely used to reconstruct paleohydrological/climatic changes, but many species are also known to respond to pollutants. Peatlands around the world have been exposed to anthropogenic and intermittent natural pollution through the late Holocene. This raises the question: can pollution lead to changes in the testate amoeba paleoecological record that could be erroneously interpreted as a climatic change? To address this issue we applied testate amoeba transfer functions to the results of experiments adding pollutants (N, P, S, Pb, O3) to peatlands and similar ecosystems. We found a significant effect in only one case, an experiment in which N and P were added, suggesting that pollution-induced biases are limited. However, we caution researchers to be aware of this possibility when interpreting paleoecological records. Studies characterising the paleoecological response to pollution allow pollution impacts to be tracked and distinguished from climate change.

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Yeates, Gregor W., and Wilhelm Foissner. "Testate amoebae as predators of nematodes." Biology and Fertility of Soils 20, no. 1 (April 1995): 1–7. http://dx.doi.org/10.1007/bf00307834.

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Smith, Humphrey Graham, Anatoly Bobrov, and Enrique Lara. "Diversity and biogeography of testate amoebae." Biodiversity and Conservation 17, no. 2 (October 16, 2007): 329–43. http://dx.doi.org/10.1007/s10531-007-9260-9.

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González López, Laura, Juan Ramón Vidal Romaní, María José López Galindo, Marcos Vaqueiro Rodríguez, and Jorge Sanjurjo Sánchez. "First data on testate amoebae in speleothems of caves in igneous rocks." Cadernos do Laboratorio Xeolóxico de Laxe. Revista de Xeoloxía Galega e do Hercínico Peninsular 37 (December 9, 2013): 37–55. http://dx.doi.org/10.17979/cadlaxe.2013.37.0.3581.

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The testate amoebae form part of the habitual troglobios in caves developed in igneous rocks (plutonic and volcanic) where the little light, the persistence of humidity, the availability of silica and organic matter allow these protozoa to develop their biological cycle. This work presents a first inventory of species of amoebae testate identified in caves in igneous rocks from different parts of the World.

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Bobrov, A. A. "Shell Amebas of the Natural and Historical Park “Bitsevsky Forest”, Moscow." Известия Российской академии наук. Серия биологическая, no. 6 (November 1, 2023): 700–705. http://dx.doi.org/10.31857/s1026347023600036.

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For the first time in protozoology, research was carried out on the fauna of testate amoebae in a city park. One hundred and nine species and infraspecific taxa of this group of free-living protozoa were found in various types of habitats in the Bitsevsky Forest park in Moscow. To assess the species diversity of testate amoebae, samples were taken from tree hollows; small oligo-mesotrophic swamps; epiphytic mosses from tree trunks; mosses on deadwood; bottom samples from reservoirs; soil samples near tree trunks, as well as directly in the area of the Yasenevo park estate. Various ecological groups of testate amoebae have been identified, the richest communities of eurybionts inhabited soils, as well as mosses on deadwood. Bottom sediments of manor ponds were inhabited mainly by hydrophilic species of the genus Difflugia.

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Miranda, Viviane Bernardes dos Santos, Tatiane Mantovano, Yemna Gomes da Silva, Fábio Amodêo Lansac-Tôha, and Rosana Mazzoni. "Occurrence of Arcellidae (Amorphea, Arcellinida) in a coastal stream in the State of Rio de Janeiro." Acta Scientiarum. Biological Sciences 42 (August 24, 2020): e52710. http://dx.doi.org/10.4025/actascibiolsci.v42i1.52710.

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The aim of this study was to elaborate a taxonomic survey on the testate amoebae of the Family Arcellidae in coastal streams in the State of Rio de Janeiro. Six samplings were conducted in Ubatiba coastal stream (Maricá, RJ). In total, 130 liters water were filtered through a conical net of 60-μm mesh and preserved in 4% formalin. Organisms were identified with the aid of an inverted trinocular microscope. The morphological characteristics (lobose testate amoebae with shell composed of granular chitinoid elements) of each species were recorded. The species were described and illustrated. For the verification of new taxa records of Arcellidae in Rio de Janeiro and their distribution in Brazil, a search based on index articles by Scopus, Web of Science and Google Scholar using the keywords "tecamebas", "testate amoebae", "Arcella", "Arcellidae", "Brazil" and "Rio de Janeiro", was performed. Eight Arcellidae species were recorded. Some ecological and taxonomic information was provided. Due to the small amount of information on testate amoebae, this study is important because it reduces the knowledge gap regarding this community in the State of Rio de Janeiro. Furthermore, we suggest new studies on species identification to be conducted to expand regional knowledge about these organisms.

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Kutluk, Hatice, and Yuri Mazei. "Organic-walled Fossil Testate Amoebae Records (late Cretaceous–holocene) from the Neotethyan–mediterranean Region." Journal of Foraminiferal Research 48, no. 2 (April 20, 2018): 121–41. http://dx.doi.org/10.2113/gsjfr.48.2.121.

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Abstract The significance of fossil testate amoebae having organic shells and their application for biostratigraphical and paleoecological studies are unexplored fields, although these organisms are extensively used as bioindicators in ecological studies of Recent and Holocene environments. Some taxa of fossil testate amoebae with organic (chitinous, pseudochitinous, or proteinaceous) shells were recovered in Turkey from a series of palynological samples, ranging in age from Late Cretaceous to Holocene. A total of 202 samples were processed from sediments from 11 sites representing fluvial flood-plain, lacustrine, estuarine, and peat-swamp as well as shallow and deep marine facies. Nineteen taxa of the genera Arcella, Centropyxis, Frenzelina, Microcometes, Nebela, Phryganella, Pyxidicula, and Sphenoderia were recorded from the Late Cretaceous, Lower−Middle Eocene, Lower Miocene, and Quaternary sediments. The literature on fossil organic-walled testate amoebae records was also reviewed and compared with the findings in this study.

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Kornecki, Krystyna M., and Miriam E. Katz. "Profundal Testate Amoebae (Arcellacea) of Lake Superior and Lake Michigan." Journal of Foraminiferal Research 50, no. 1 (January 1, 2020): 3–10. http://dx.doi.org/10.2113/gsjfr.50.1.3.

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Abstract Sediment surface death assemblages of recent testate amoebae (Arcellacea) are reported from nine sites in Lake Superior and Lake Michigan. These are the first profundal sediment-water interface samples of testate amoebae described from either of the Great Lakes which provide valuable insight on deep-water, large-lake assemblages. Centropixid strains were present to abundant in shallower, nearshore sites (up to 66 m water depth). Assemblages at depths >40 m were dominated by Difflugia oblonga “tenuis.” The shallowest sample (26 m) was dominated by Centropyxis aculeata “discoides” and Difflugia oblonga “tenuis.” Over 100 tests per sample were observed from >100 m. Density of tests appears to be constrained by lithology rather than water depth. The deepest site (325 m) yielded low foraminiferal abundances. This pilot study provides a first step towards documenting the distribution of testate amoebae in the Great Lakes.

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Korganova, Galina A. "Soil fauna in pine forests of Poland: Testate Amoebae (Protozoa, Testacea)." Fragmenta Faunistica 36, no. 1-12 (1993): 37–50. http://dx.doi.org/10.3161/00159301ff1993.36.3.037.

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Bankov, Nikola, Milcho Todorov, and Anna Ganeva. "Checklist of Sphagnum-dwelling testate amoebae in Bulgaria." Biodiversity Data Journal 6 (May 22, 2018): e25295. http://dx.doi.org/10.3897/bdj.6.e25295.

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Until now, a complete checklist of Sphagnum-dwelling testate amoebae in Bulgaria has never been published. Records for species diversity and distribution in the country were scattered in many faunistic and ecological publications. The aim of the present study is to summarise all data for the species distribution at the level of country by reviewing the existing literature and by additional data obtained in our research over the past two years. The checklist comprises 171 species, classified into 43 genera, 20 families, three orders, three classes and three phyla. We present data for 16 new Sphagnum-dwelling testate amoebae in Bulgaria and new distribution data for 134 species. Of them, 99 species are recorded from Stara Planina Mt., for which there was no available data to date. Additionally are recorded 69 new species for Pirin Mt., 21 for Vitosha Mt. and 18 for Rila Mt. Thirty six species are synonymised according to the latest taxonomic changes. Two misidentified taxa (Euglyphabrachiata Penard, 1902 and Difflugiacompressavar.africana Gauthier-Lièvre et Thomas, 1958) are transferred into valid species E.acanthophora and Zivkoviciacompressa, respectively. Three of the recorded species have not been included in the checklist, because they are currently not refering to testate amoebae (Cochliopodiumbilimbosum (Auerbach 1856) and Cochliopodiumechinatum Korotneef, 1879 are gymnamoebae (naked amoebae) and Microgromiaelegantula (Penard 1904) = Paralieberkuehniaelegantula (Penard 1904) is freshwater foraminifera).

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Snegovaya, N. Yu, and E. N. Tahirova. "A New Species Of Testate Amoebae Of The Genus Difflugia From The Freshwaters Of Azerbaijan (Rhizopoda, Testacea, Difflugiidae)." Vestnik Zoologii 49, no. 2 (April 1, 2015): 99–104. http://dx.doi.org/10.1515/vzoo-2015-0010.

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Abstract A new testate amoebae species Difflugia alekperovi sp. n. was found during a faunistic study of inland waters of Lenkoran Region, South-Eastern Azerbaijan. The morphology and biometry of this species was described by LM and SEM investigations.

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Jung, Jongwoo. "New Records of Testate Amoebae from Korea." Korean Journal of Environmental Biology 34, no. 4 (December 31, 2016): 314–19. http://dx.doi.org/10.11626/kjeb.2016.34.4.314.

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Charman, Dan J. "Biostratigraphic and palaeoenvironmental applications of testate amoebae." Quaternary Science Reviews 20, no. 16-17 (October 2001): 1753–64. http://dx.doi.org/10.1016/s0277-3791(01)00036-1.

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Ellison, Robert L. "Paleolimnological analysis of Ullswater using testate amoebae." Journal of Paleolimnology 13, no. 1 (January 1995): 51–63. http://dx.doi.org/10.1007/bf00678110.

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Opravilová, Vera, and Svetlana Zahrádková. "Some information on testate amoebae of Iceland." Limnologica 33, no. 2 (July 2003): 131–37. http://dx.doi.org/10.1016/s0075-9511(03)80042-7.

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Gonçalves Araujo, Ronnilda Maria, Guilherme Sampaio Cabral, Fabiano Corrêa, and André Ricardo Ghidini. "Effects of urbanization on the diversity of testate amoebae (Protist, Rhizopoda) in a stream of the southwestern Amazon basin (Igarapé São Francisco in Acre state, Brazil)." Acta Protozoologica 62 (2023): 25–37. http://dx.doi.org/10.4467/16890027ap.23.003.18283.

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We investigated the diversity of testate amoebae in an urban stream located within the Igarapé São Francisco Environmental Protection Area in Acre, northern Brazil, during the dry season, and evaluated the factors mediating the structure of this protist community. We collected 108 water samples for the analysis of the testate amoeba community and the limnological variables at six sampling points on the stream, between July and September 2018. We used a Redundancy Analysis (RDA) to verify the influence of environmental variables on the protist community. We recorded 76 species of testate amoebae from eight families, with most records from the families Difflugiidae, Arcellidae, Centropydae and Netzeliidae. More than half (49) of the species were recorded in Acre for the first time. The abundance of the amoebae of the family Trigonopiridae was regulated by the dissolved oxygen concentrations and the pH, while that of the Netzeliidae, Dif-flugiidae and Lesquereusidae was influenced by the pH, chloride concentrations, and the depth and transparency of the water. In the case of the family Arcellidae, abundance was determined by the turbidity and transparency of the water and the nitrate concentrations, while that of Centropyxis sp. was associated with the concentrations of thermotolerant coliforms. These findings indicate that, while the São Francisco stream is subject to anthropogenic impacts, it still presents adequate conditions for these organisms in some of its stretches. The abundance of these amoebae was influenced primarily by the productivity of the system, as indicated by the high protist densities recorded in the areas in which primary productivity was highest. These findings support the use of these protists in studies that investigate the most appropriate indicator organisms that respond to anthropogenic impacts and shifts in environmental quality.The results of the present study demonstrated the importance of this aquatic ecosystem for the biodiversity of the study area, and the need to further expand our knowledge on the adaptations and interactions of the aquatic communities of the Amazon region.

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Golemansky, Vassil. "SYNTHESIS OF THE BULGARIAN PROTOZOOLOGICAL INVESTIGATIONS OF SOUTH SHETLAND ISLANDS (THE ANTARCTIC)." Ecologica Montenegrina 5 (February 17, 2016): 47–56. http://dx.doi.org/10.37828/em.2016.5.9.

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Within the range of the Bulgarian Antarctic Program (1987-2010) some parasitological investigations on the coccidian parasites of 3 penguin species from South Shetland Islands (Livingston and St George Islands) were conducted, namely: Pygoscelis antarctica, P. papua and P. adeliae. Three coccidian species were found, one of which was described as a new species: Eimeria pygosceli Golemansky, 2003. It was isolated from the fecal samples of all 3 penguin species, living at South Shetland Islands. The other not identified coccidian’s were of the genera Eimeria and Isopspora. (Table 1). The great number of coccidian’s oocysts in some of the examined birds (from 80 – 220 oocysts in one microscopic field) suggest for their pathogenic role on the penguin’s population.As a result of our studies on some soil, moss and freshwater habitats from Livingston Island a total of 48 rhizopods were found. Three of them were naked amoebae of the genera Hartmanella, Thecamoeba and Vannella and the other 45 species were testate amoebae of 17 genera. Data on their occurrence frequency (pF) and dominance frequency (DF) were given (Table 2). The research on the marine interstitial testate amoebae from the supralittoral of the Antarctic region of Chile and Livingston Island shows the presence of 17 species of psammobiotic and psammophilous testate amoebae (Table 3).

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Caballero, Margarita, Itzel Sigala, Joanna Moreno, Mireya Vega-Flores, Luis A. Oseguera, Ana Carolina Ruiz-Fernández, and Javier Alcocer. "Testate amoebae assemblages from two tropical high-mountain lakes in central Mexico during the last ~60 years." Revista Mexicana de Biodiversidad 93 (December 7, 2022): e934168. http://dx.doi.org/10.22201/ib.20078706e.2022.93.4168.

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Testate amoebae are bioindicators sensitive to environmental change, which show good preservation in sediments of low pH environments, such as high mountain lakes (LAM). The presence and diversity of testate amoebae were documented in surface sediments and sediment cores, dated with 210Pb, from the only 2 LAMs in Mexico (El Sol and La Luna), which have shown signs of recent human-induced changes. A total of 18 taxa were recorded and the main species observed in both lakes were Difflugia glans “glans” and D. globulosa. Specific richness and Shannon’s diversity index were higher in Lake El Sol than in the smaller, acidic and ultraoligotrophic Lake La Luna. The sediment cores recorded changes, during the last 20 to 25 years, in the composition of the testate amoebae communities (El Sol) and in their dominance (La Luna), as well as increased accumulation rate and concentrations of iron and organic carbon. These are signs of anthropogenic impact on the lakes, which should alert us to improve protection measures for these unique ecosystems, not only at the local (crater) level, but also with a more regional perspective.

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Łuców, Dominika, Mariusz Lamentowicz, Milena Obremska, Maria Arkhipova, Piotr Kittel, Edyta Łokas, Andrey Mazurkevich, Tomasz Mróz, Rik Tjallingii, and Michał Słowiński. "Disturbance and resilience of a Sphagnum peatland in western Russia (Western Dvina Lakeland) during the last 300 years: A multiproxy, high-resolution study." Holocene 30, no. 11 (July 14, 2020): 1552–66. http://dx.doi.org/10.1177/0959683620941064.

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This paper presents the results of multiproxy research (pollen, charcoal, plant macrofossil and testate amoebae) on the biogenic deposits core from Gorodetsky Moch, an ombrotrophic peatland in western Russia (Western Dvina Lakeland). We reconstructed the impact of disturbance on peatland development in the last 300 years by using chronology of the records based on 14C and 210Pb data set. The multiproxy reconstruction was compared with changes in the land cover using historical maps and Corona images, which provides a unique spatial analysis of past ecological and land-use changes. We aimed to determine the effect of local disturbances (drainage) and land-use changes (landscape openness) on the development of the peatland during the last 300 years. Our study suggests that human activity had a crucial impact on the development of the peatland in the last centuries. The analysis of testate amoebae and plant macrofossils revealed a clear disturbed layer in the second half of the 20th century CE. Most probably, the drainage of the peatland triggered changes in the community of testate amoebae and plants, thereby causing a functional shift in Sphagnum peatland ecosystem. The hydrological stress and vegetation composition shift led to the collapse of mixotrophic testate amoebae. However, the peatland showed strong resilience and recovered toward the end of the 20th century CE and the beginning of the 21st century CE, despite the lower water table. Our study shows an example of the peatland ecosystem that experienced a considerable stress but finally sustained the former function.

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Nolan, Connor, John Tipton, Robert K. Booth, Mevin B. Hooten, and Stephen T. Jackson. "Comparing and improving methods for reconstructing peatland water-table depth from testate amoebae." Holocene 29, no. 8 (May 9, 2019): 1350–61. http://dx.doi.org/10.1177/0959683619846969.

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Proxies that use changes in the composition of ecological communities to reconstruct temporal changes in an environmental covariate are commonly used in paleoclimatology and paleolimnology. Existing methods, such as weighted averaging and modern analog technique, relate compositional data to the covariate in very simple ways, and different methods are seldom compared systematically. We present a new Bayesian model that better represents the underlying data and the complexity in the relationships between species’ abundances and a paleoenvironmental covariate. Using testate amoeba–based reconstructions of water-table depth as a test case, we systematically compare new and existing models in a cross-validation experiment on a large training dataset from North America. We then apply the different models to a new 7500-year record of testate amoeba assemblages from Caribou Bog in Maine and compare the resulting water-table depth reconstructions. We find that Bayesian models represent an improvement over existing methods in three key ways: more complete use of the underlying compositional data, full and meaningful treatment of uncertainty, and clear paths toward methodological improvements. Furthermore, we highlight how developing and systematically comparing methods lead to an improved understanding of the proxy system. This paper focuses on testate amoebae and water-table depth, but the framework and ideas are widely applicable to other proxies based on compositional data.

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Korganova, G. A., and A. A. Rakhleeva. "Testate amoebae (Testacea) in a Formica lugubris nest: Fauna composition and structure." Entomological Review 86, S2 (March 2006): S189—S200. http://dx.doi.org/10.1134/s0013873806110133.

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Porter, Susannah M., and Andrew H. Knoll. "Testate amoebae in the Neoproterozoic Era: evidence from vase-shaped microfossils in the Chuar Group, Grand Canyon." Paleobiology 26, no. 3 (2000): 360–85. http://dx.doi.org/10.1666/0094-8373(2000)026<0360:taitne>2.0.co;2.

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Vase-shaped microfossils (VSMs) occur globally in Neoproterozoic rocks, but until now their biological relationships have remained problematic. Exceptionally preserved new populations from the uppermost Chuar Group, Grand Canyon, Arizona, display details of morphology and taphonomy that collectively point to affinities with the testate amoebae. The fossils are tear-shaped tests, ∼20–300 μm long and ∼10–200 μm wide, that are circular in transverse section, expand aborally toward a rounded or slightly pointed pole, and taper orally toward a “neck” that ends in a single aperture. Apertures may be circular, hexagonal, triangular, or crenulate, and may be rimmed by a distinct collar. Approximately 25% of the Chuar VSMs are curved, such that the oral and aboral poles do not lie opposite each other. Tests are preserved as mineralized casts and molds, commonly coated with organic debris or iron minerals, but they were originally composed of nonresistant organic matter. Approximately 1% have a “honeycomb-patterned” wall attributable to the original presence of mineralized scales whose bases were arranged regularly in the test wall. Scale-bearing testate amoebae, such as members of the Euglyphidae, are essentially identical to the honeycomb VSMs, and a close relationship between other Grand Canyon VSMs and additional testate amoebae, both lobose and filose, is likely. The VSM population therefore most likely represents a multispecies assemblage whose spatial association reflects a common habitat and/or taphonomic circumstances that favor test preservation. The assignment of these fossils to the testate amoebae strengthens the case for a major diversification of eukaryotic organisms by mid-Neoproterozoic times and, more significantly, provides the earliest morphological evidence for heterotrophic eukaryotes in marine ecosystems.

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Lansac-Tôha, FA, LFM Velho, DM Costa, NR Simões, and GM Alves. "Structure of the testate amoebae community in different habitats in a neotropical floodplain." Brazilian Journal of Biology 74, no. 1 (February 2014): 181–90. http://dx.doi.org/10.1590/1519-6984.24912.

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This study evaluated the differences in composition, abundance and morphology of testate amoebae among different habitats of the same aquatic environment (plankton, aquatic macrophyte and sediment) in the Upper Paraná River floodplain. Triplicate samplings were undertaken monthly at each habitat from April 2007 to March 2008. The structure of the community of testate amoebae was different among the habitats. The species typical for each habitat, according to Indval, were classified by their shell morphology. Arcella species together with Difflugia gramen and Difflugia pseudogramem were more abundant for plankton. Trinema and Phryganellastood out by their abundance and frequency in aquatic macrophytes. Centropyxis was an indicator of sediment. The results indicated a higher frequency of hemispherical and spherical shells in plankton and spherical and elongated shells in aquatic macrophytes. In the sediment, there was a high frequency of elongated species. Our results support the hypothesis that the community of testate amoebae has different structures among the habitats, refuting the idea that the organization of this community in plankton is guided by random events like the resuspension of organisms from the sediment and their displacement from marginal vegetation.

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Charman, Dan J., W. Roland Gehrels, Clare Manning, and Charu Sharma. "Reconstruction of recent sea-level change using testate amoebae." Quaternary Research 73, no. 2 (March 2010): 208–19. http://dx.doi.org/10.1016/j.yqres.2009.11.009.

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Proxy-based sea-level reconstructions place the instrumentally observed rates of recent sea-level rise in a longer term context by providing data that extend the instrumental sea-level record into past centuries. This paper presents the first sea-level reconstructions based on analyses of testate amoebae, to test their ability to produce high-precision reconstructions of past sea level. We present two reconstructions for the past 100"yr from sites in Maine (USA) and Nova Scotia (Canada) based on short cores from salt marshes, and modern training data from North America and the United Kingdom. These are compared with tide-gauge records and reconstructions based on foraminifera from the same cores. The reconstructions show good agreement with both the tide-gauge data and the foraminifera-based reconstructions. The UK data perform well in predicting known elevations of North American surface samples and produce sea-level reconstructions very similar to those based on the North American data, suggesting the methodology is robust across large geographical areas. We conclude that testate amoebae have the potential to provide robust, higher precision sea-level reconstructions for the past few centuries if modern transfer functions are improved and core sites are located within the main zone of testate amoebae occurrence on the salt marsh.

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Sigala, Itzel, Socorro Lozano-García, Jaime Escobar, Liseth Pérez, and Elvia Gallegos-Neyra. "Testate Amoebae (Amebozoa: Arcellinida) in Tropical Lakes of Central Mexico." Revista de Biología Tropical 64, no. 1 (June 28, 2016): 377. http://dx.doi.org/10.15517/rbt.v64i1.18004.

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Testate amoebae are common single-celled eukaryotic organisms in aquatic ecosystems. Despite their important role in these ecosystems, and their potential as bioindicators and paleoindicators, they remain poorly studied in Mexico. The major objectives of this study were to: 1) increase knowledge of testate amoebae in Mexico’s tropical lakes, and 2) create a catalog of high-quality scanning electron micrographs that can be used for future ecological and paleoenvironmental studies. We collected surface-sediment samples from 29 lakes, located in the Transmexican Volcanic Belt, one at each lake during June and October 2011, and March 2013. Sediments were collected with an Ekman grab and preserved in anhydrous ethanol. Sub-samples were observed under a stereomicroscope and morphometric data for each species were recorded. Total diameter and aperture diameter were measured on circular tests. Irregularly shaped tests were measured for length and width of the aperture and for the size of the whole test. If a specimen possessed spines, the length of one randomly selected spine was measured. The best-preserved specimen of each taxon was photographed with an optical microscope and a scanning electron microscope (SEM). We found 41 taxa of testate amoebae belonging to the genera: Arcella, Centropyxis, Cucurbitella, Cyclopyxis, Cyphoderia, Difflugia, Euglypha, Lesquereusia, Pentagonia, Pseudodifflugia and Scutiglypha. Twelve species not previously reported for Mexico were recorded, along with 13 varieties. The average number of taxa recorded in each lake was eight, and the highest taxonomic richness was 18. The taxon found in the greatest number of lakes was Centropyxis aculeata var. aculeata. Taxonomic richness varied among lakes in the same region. This could reflect lake-specific differences in environmental conditions, underscoring the need for more detailed studies that include collection of data on physical and chemical variables in the lakes. Our results highlighted the need of further studies for the distribution patterns and ecology of lacustrine testate amoebae.

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Yang, Jun, Wenjing Zhang, Weisong Feng, and Yunfen Shen. "Testate Amoebae (Protozoa: Rhizopoda) from Northwest Yunnan, China." Journal of Freshwater Ecology 20, no. 3 (September 2005): 583–90. http://dx.doi.org/10.1080/02705060.2005.9664774.

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VINCKE, SOFIE, PIETER LEDEGANCK, LOUIS BEYENS, and BART VAN DE VIJVER. "Soil testate amoebae from sub-Antarctic Îles Crozet." Antarctic Science 16, no. 2 (June 2004): 165–74. http://dx.doi.org/10.1017/s0954102004001993.

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An ecological study of the soil testate amoebae (Protozoa, Rhizopoda) communities on the sub-Antarctic island of Île de la Possession (Îles Crozet) revealed 65 taxa, belonging to 20 genera. Trinema lineare and Euglypha laevis were the most dominant species in all types of soils on the island. A Redundancy Analysis revealed three communities that characterize specific habitats: i. fellfield soils, characterized by low moisture values and low organic material content, contained fewer taxa and fewer individuals, ii. peaty valley soils, with lower pH values, showed high abundances and diversity, and iii. soils influenced by sea spray and marine animals had higher nutrient contents, elevated chloride and conductance values, resulting in more tests of Difflugiella oviformis, Nebela dentistoma and Edaphonobiotus campascoides. Special attention was given to the species composition in relation to the soil type and its moisture content. A comparison with aquatic habitats on Île de la Possession was made.

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Swindles, Graeme T., Mariusz Lamentowicz, Monika Reczuga, and Jennifer M. Galloway. "Palaeoecology of testate amoebae in a tropical peatland." European Journal of Protistology 55 (September 2016): 181–89. http://dx.doi.org/10.1016/j.ejop.2015.10.002.

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Qin, Yangmin, Richard Payne, Yansheng Gu, Yuri Mazei, and Yanxin Wang. "Short-term response of testate amoebae to wildfire." Applied Soil Ecology 116 (August 2017): 64–69. http://dx.doi.org/10.1016/j.apsoil.2017.03.018.

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Santiago-Vera, Josue, and Alonso Ramírez. "MEIOFAUNA IN TROPICAL MONTANE STREAMS: BIOTIC AND ABIOTIC FACTORS REGULATING COMMUNITIES." Acta Biológica Colombiana 28, no. 2 (May 8, 2023): 229–38. http://dx.doi.org/10.15446/abc.v28n2.103379.

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Meiofauna is a group of heterotrophic organisms smaller than macroinvertebrates but larger than microfauna and characterized by groups such as testate amoebae, ciliates, and nematodes. They are a link between bacteria and resources and macroinvertebrates. However, tropical meiofauna is poorly studied; thus, our goal was to characterize meiofaunal community composition and abundance and assess potential environmental variables controlling these community dynamics. Monthly samplings of meiofauna were conducted for eight months in Quebrada Prieta, El Yunque National Forest, Puerto Rico. Sampling was made in 12 pools, and data on discharge, sediment characteristics, and biotic variables were also collected. A total of 62 meiofaunal morphospecies were identified, with nematodes dominating the community, followed by testate amoebae. Bacterivores and detritivores taxa dominated the community. Meiofaunal abundance was negatively related to discharge and positively to the percentage of coarse sand, nitrate, and macroinvertebrate abundance. The composition of meiofauna in Quebrada Prieta is like the composition reported for temperate streams, at least in major meiofaunal groups present. However, the community in Quebrada Prieta was dominated by testate amoebae. In contrast, temperate streams are often dominated by rotifers and nematodes. Both abiotic and biotic variables are important for meiofaunal communities in the headwater streams in Puerto Rico.

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Saldaev, Damir, Kirill Babeshko, Viktor Chernyshov, Anton Esaulov, Xiuyuan Gu, Nikita Kriuchkov, Natalia Mazei, et al. "Biodiversity of Terrestrial Testate Amoebae in Western Siberia Lowland Peatlands." Data 8, no. 11 (November 17, 2023): 173. http://dx.doi.org/10.3390/data8110173.

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Testate amoebae are unicellular eukaryotic organisms covered with an external skeleton called a shell. They are an important component of many terrestrial ecosystems, especially peatlands, where they can be preserved in peat deposits and used as a proxy of surface wetness in paleoecological reconstructions. Here, we represent a database from a vast but poorly studied region of the Western Siberia Lowland containing information on TA occurrences in relation to substrate moisture and WTD. The dataset includes 88 species from 32 genera, with 2181 incidences and 21,562 counted individuals. All samples were collected in oligotrophic peatlands and prepared using the method of wet sieving with a subsequent sedimentation of aqueous suspensions. This database contributes to the understanding of the distribution of testate amoebae and can be further used in large-scale investigations.

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Journal articles on the topic 'Testate amoebae'

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