Foraminifera and thecamoebians are highly sensitive to environmental stress (natural or anthropogenic). This feature means that they can be used to biologically characterize a variety of freshwater and coastal marine environments. Due to their small size and hard shells, large quantities are also found fossilised in core samples, making them ideal for reconstructing past environmental conditions. This volume covers the specific environmental applications of these organisms and contains an introduction to the subject, detailed descriptions of methods and techniques and case studies. Written for non-specialists, this book will appeal to resource managers and consultants in the public and private sector who routinely work on coastal environmental problems. The book will also serve as a supplementary text for graduate students in many courses on environmental monitoring, ecological baseline studies and environmental science.

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Some of the relatively recent literature correlating morphological variation in benthic foraminifera with environmental parameters such as temperature, salinity, carbonate solubility, depth, nutrition, substrate, dissolved oxygen, illumination, pollution, water motion, trace elements, and rapid environmental fluctuation is reviewed. It appears some variables (most notably depth) are recorded more frequently, which may affect some conclusions. Although each variable is treated separately, it appears that almost no variables act independently on test morphologies. In reviewing the literature, it becomes clear that there are many individual trends, especially with shell ornamentation, but few broad ones, and that it is almost impossible, with exception of some of the larger reef-dwelling, symbiont-bearing foraminifera, to predict how any species will react to various parameters. The broad trends concern thinning or thickening of carbonate tests with changing carbonate availability, temperature, and salinity. It appears that many observations of morphological changes within species may not be recorded in the literature, perhaps because authors did not recognize the importance of small details that would be of importance at a later time.

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Cores dating back to deglaciation were taken from three lakes in Atlantic Canada and analyzed for arcellaceans and pollen. Paleotemperatures and paleo-precipitation were calculated from the pollen data using transfer functions. A sudden warming is recorded by the pollen around 10,000 years B.P., followed by a general warming to the mid Holocene Hypsithermal, then by a decrease in temperature and increase in effective precipitation to the present. The three lakes, two in western Newfoundland and one in eastern Nova Scotia, contain similar late glacial (13-10 ka), early Holocene (10-8 ka), mid Holocene (8-4 ka), and late Holocene (4-0 ka) arcellacean assemblages. Immediately following retreat of the ice sheets, Centropyxis aculeata, Centropyxis constricta, Difflugia oblonga, Difflugia urceolata, and Difflugia corona were common. The latter part of the late glacial is characterized by sparse assemblages dominated by C. aculeata. The arcellacean record thus suggests a climatic reversal in Atlantic Canada between 11,500 and 10,000 years B.P., analogous to the Younger Dryas, although this is not recorded by the pollen. Species diversity increased sharply at the beginning of the Holocene, and D. oblonga is the dominant taxon in early Holocene sediments. Difflugia oblonga remained common through the mid Holocene, but percentages of C. aculeata were very low, and Pontigulasia compressa and Difflugia bacillifera peaked in abundance during the Hypsithermal. The late Holocene is characterized by a resurgence in C. aculeata at the expense of other taxa. The increase in Heleopera sphagni and Nebella collaris since 5,000 years B.P. at the two sites in southwestern Newfoundland reflects paludification in response to increased precipitation since the Hypsithermal. Because the changes in arcellacean assemblages are regionally synchronous in all three lakes and coincide with climatically driven vegetational successions indicated by the pollen record, arcellaceans appear to respond to climatic change, and thus may be useful paleoecological and paleolimnological indicators. With their quicker generation time, these protists may be better suited than pollen to recording short-lived phenomena, like the mid-Holocene Hypsithermal and the Younger Dryas reversal.