Investigating the potential of thecamoebians (testate amoebae) as bio-indicators of impact of oil sands mining operations on freshwater environments in Northeastern Alberta, Canada

Thecamoebian (testate amoeba) species diversity and assemblages in reclamation wetlands and lakes in northeastern Alberta respond to chemical and physical parameters associated with oil sands extraction. Ecosystems more impacted by OSPM (oil sands process-affected material) contain sparse, low-diversity populations dominated by centropyxid taxa and Arcella vulgaris. More abundant and diverse thecamoebian populations rich in difflugiid species characterize environments with lower OSPM concentrations. These shelled protists respond quickly to environmental change, allowing year-to-year variations in OSPM impact to be recorded. Their fossil record thus provides corporations with interests in the Athabasca Oil Sands with a potential means of measuring the progression of highlyimpacted aquatic environments to more natural wetlands. Development of this metric required investigation of controls on their fossil assemblage (e.g. seasonal variability, fossilization potential) and their biogeographic distribution, not only in the constructed lakes and wetlands on the oil sands leases, but also in natural environments across Alberta.

Freshwater dinoflagellates as proxies of cultural eutrophication: a case study from Crawford Lake, Ontario

Crawford Lake, Ontario, provides an ideal natural laboratory to study the response of freshwater dinoflagellates to cultural eutrophication. The anoxic bottom waters that result from meromixis in this small (2.4 ha) but deep (24 m) lake preserve varved sediments that host an exceptional fossil record. These annual layers provide dates for human activity (agriculture and land disturbance) around the lake over the last millennium by both Iroquoian village farmers (ca. A.D. 1268-1486) and Canadian farmers beginning ~A.D. 1883. The well established separate intervals of human activity around Crawford Lake, together with an abundance of available data from other fossil groups, allow us to further investigate the potential use of the cyst of freshwater dinoflagellates in studies of eutrophication. Cyst morphotypes observed have been assigned as Peridinium willei Huitfeldt-Kaas, Peridinium wisconsinense Eddy and Peridinium volzii Lemmermann and Parvodinium inconspicuum (Lemmermann) Carty. The latter two cyst-theca relationships were determined by culturing and by the exceptional preservation of thecae of P. inconspicuum in varves deposited at times of anthropogenic reductions in dissolved oxygen.