A paleolimnological record of Holocene climate and environmental change in the Temagami region, northeastern Ontario

Boudreau, Robert E.A.; Galloway, Jennifer M.; Patterson, R. Timothy; Kumar, Arun; Michel, Frederick A.

doi:10.1007/s10933-004-7616-7

Cited by 48 publications

(33 citation statements)

References 39 publications

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“…Research on testate amoebae during the past few years has resulted in great progress on realizing the potential of this group as an important new class of palaeoenvironmental indicator (Patterson and Kumar 2002 and references therein;Bobrov et al 2004;Boudreau et al 2005). Unfortunately, only single rhizopod remains were found in our study, and some rhizopod-based palaeoenvironment inferences are problematic.…”

Section: General Interpretation Of Palaeoenvironment During the Last mentioning

confidence: 77%

Interglacial History of a Palaeo-lake and Regional Environment: A Multi-proxy Study of a Permafrost Deposit from Bol’shoy Lyakhovsky Island, Arctic Siberia

et al. 2006

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Chironomid, pollen, and rhizopod records from a permafrost sequence at Bol'shoy Lyakhovsky Island (New Siberian Archipelago) document the development of a thermokarst palaeo-lake and environmental conditions in the region during the last Interglacial (MIS 5e). Open Poaceae and Artemisia associations dominated vegetation at the beginning of the interglacial period. Rare shrub thickets (Salix, Betula nana, Alnus fruticosa) grew in more protected and wetter places as well. Saalian ice wedges started to melt during this time, resulting in the formation of an initial thermokarst water body. The high percentage of semiaquatic chironomids suggests that a peatland-pool initially existed at the site. A distinct decrease in semiaquatic chironomid taxa and an increase in lacustrine ones point to a gradual pooling of water in the basin, which could in turn induce thermokarst and create a permanent pond during the subsequent period. The highest relative abundance of Chironomus and Procladius reflects unfrozen water remaining under the ice throughout the ice-covered period during the later stage of palaeo-lake development. The chironomid record points to three successive stages during the history of the lake: (1) a peatland pool; (2) a pond (i.e., shallower than the maximum ice-cover thickness); and (3) a shallow lake (i.e., deeper than the maximum ice-cover thickness). The trend of palaeo-lake development indicates that intensive thermokarst processes occurred in the region during the last Interglacial. Shrub tundra communities with Alnus fruticosa and Betula nana dominated the vegetation during the interglacial optimum. The climate was moister and warmer than present. The results of this study suggest that quantitative chironomid-based temperature reconstructions from Arctic thermokarst ponds/lakes may be problematic due to other key environmental factors, such as prolonged periods of winter anoxia and local hydrological/geomorphological processes, controlling the chironomid assemblages.

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Section: General Interpretation Of Palaeoenvironment During the Last mentioning

confidence: 77%

Interglacial History of a Palaeo-lake and Regional Environment: A Multi-proxy Study of a Permafrost Deposit from Bol’shoy Lyakhovsky Island, Arctic Siberia

et al. 2006

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“…Centropyxis aculeata strain "aculeata" has been reported from temperate latitudes as an opportunistic species and an indicator of hostile environmental conditions, such as high salinity and conductivity levels , high contamination by heavy metals (Roe et al, 2010) and cooling events (Boudreau et al, 2005). In tropical water bodies, the highest abundance of this species is associated with cold periods (winter season) and a relatively low humidity (Farooqui et al, 2012).…”

Section: Centropyxis Aculeata Strain "Aculeata" Assemblagementioning

confidence: 99%

Ecological drivers of testate amoeba diversity in tropical water bodies of central Mexico

et al. 2018

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Testate amoebae are unicellular organisms characterized by a shell-like test. Due to their potential use as bioindicators (and paleoindicators), these organisms have been increasingly studied in the last decade, particularly in temperate latitudes. This study's objective was two-fold: to identify the testate amoeba communities sampled from 29 water bodies in Mexico and to determine if their presence and distribution also made them suitable bioindicators for tropical latitudes. A total of 40 taxa were recorded within 12 genera, and six significant variables -oxygen, pH, depth, temperature, conductivity, and total alkalinity -that explained testate amoeba distribution within and among the water bodies were identified through a canonical correspondence analysis. The Q-mode clusters rendered five assemblages, each named after their respective dominant species: 1) Centropyxis aculeata strain "aculeata" assemblage, 2) Difflugia oblonga strain "bryophila" assemblage, 3) diverse assemblage, 4) Cucurbitella tricuspis assemblage, and 5) Difflugia protaeiformis strain "acuminata" assemblage. We found that Cucurbitella tricuspis and the Difflugia protaeiformis strain "acuminata" have similar ecological preferences to those reported previously for temperate lakes, with the former identified as an indicator of eutrophic environments and the latter as an indicator of low oxygen levels. On the other hand, Centropyxis aculeata strain "aculeata" and Arcella vulgaris seem to indicate adverse conditions, but the source of this environmental stress apparently differs from that reported in temperate latitudes. Although this stress source could not be identified in all cases, our study nonetheless demonstrates that testate amoebae in the water bodies of central Mexico could reveal the presence of environmental stress.

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“…Morphotypes of the same species are designated informal 'strain' names to avoid potentially unwarranted descriptions of new species (Asioli et al 1996;Patterson and Kumar 2002). Although these 'strains' are not formally recognised under the International Code of Zoological Nomenclature, many studies have proved their worth in terms of ecological indication (Boudreau et al 2005;Escobar et al 2008;Roe et al 2010;Nasser et al 2016). Testate amoebae (Salgado et al 2010) and diatoms (LEVE11) ).…”

Section: Sediment and Fossil Analysesmentioning

confidence: 99%

Refining the palaeoecology of lacustrine testate amoebae: insights from a plant macrofossil record from a eutrophic Scottish lake

et al. 2017

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Arcellinida (lobose testate amoebae) preserve well in lake sediments and have shown great potential as palaeolimnological indicators, but a limited understanding of their ecology prevents more indepth interpretations of both contemporary and fossil assemblages. Loch Leven, Scotland, has a well-documented history of nutrient-enrichment and associated lake biological change, creating a temporal gradient along which testate amoeba ecology can be investigated. Plant macrofossil data from a dated sediment core (LEVE14) indicate that a transition from oligomesotrophic to eutrophic conditions occurred over at least the last 200 years, enabling direct comparisons to be drawn with fossil testate amoeba assemblages from the same core. Cluster analysis and principal components analysis show that testate amoebae and macrophytes responded synchronously to an early phase of nutrient-enrichment after ca. AD 1200, and to anthropogenic water-level lowering and further enrichment after ca. AD 1830. The results of indicator species analysis (IndVal) support the suggestion inferred previously that Cucurbitella tricuspis is an indicator of nutrient-enrichment, while the association of some less abundant taxa, specifically Difflugia amphora and Mediolus corona, with eutrophic environments is also corroborated. Overall, the testate amoeba assemblage response appears to reflect a complex interaction of factors which were ultimately driven by eutrophication. These include variations in microhabitat associated with changing plant structure and sedimentary conditions influenced by macrophyte community succession. In particular, a shift from an oligo-mesotrophic macrophyte assemblage composed of isoetid plants to one dominated by Potamogeton spp. and dense stands of Characeae is suggested to influence the relative proportions of sediment dwelling and plant-associated testate amoebae. The results highlight the utility of testate amoebae as benthic indicators of lake nutrient-enrichment and demonstrate the value of using multi-proxy palaeolimnological data to refine the ecology of lesser-studied palaeoecological groups.

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A paleolimnological record of Holocene climate and environmental change in the Temagami region, northeastern Ontario

Cited by 48 publications

References 39 publications

Interglacial History of a Palaeo-lake and Regional Environment: A Multi-proxy Study of a Permafrost Deposit from Bol’shoy Lyakhovsky Island, Arctic Siberia

Interglacial History of a Palaeo-lake and Regional Environment: A Multi-proxy Study of a Permafrost Deposit from Bol’shoy Lyakhovsky Island, Arctic Siberia

Ecological drivers of testate amoeba diversity in tropical water bodies of central Mexico

Refining the palaeoecology of lacustrine testate amoebae: insights from a plant macrofossil record from a eutrophic Scottish lake

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