The Paleoecological Environmental Assessment and Research Lab (PEARL) is a group of over 20 research scientists, post-docs, graduate students, and other scientists dedicated to using paleolimnological techniques to provide historical perspectives to environmental change. Such data are required to define natural environmental variability, to generate and test hypotheses, and to validate the myriad of computer models that are now being generated for the study of global environmental change.

In general, PEARL is not a palynology lab, although all workers have at least a strong interest in palynology (and several incorporate palynology into their research projects). The majority of the work deals with other indicator groups, such as diatoms, chrysophyte scales and cysts, and invertebrate fossils (e.g., chironomid, Chaoborus, protozoan, etc. indicators). The group also uses a host of geochemical techniques, and collaborates with workers using different approaches.

A significant portion of PEARL's present research focuses on using surface sediment calibration sets to define the ecological optima and tolerances of paleolimnological indicators. A series of calibration or "training" sets have been completed or are now in progress spanning broad environmental and geographic gradients. Some of these calibrations focus on lake regions subjected to lake acidification (such as the Sudbury region, the Adirondack Mountain lakes, or in Scandinavia) and eutrophication (e.g., southern Ontario, British Columbia, northeastern USA). Other training sets aim to decipher the salinity optima of our indicators from western Canadian lakes (the PISCES project: Paleolimnological Investigations of Salinity, Climatic and Environmental Shifts, led mainly by Dr Brian Cumming). A large research effort is also dedicated to lakes in Arctic regions, including large transects of lakes from Whitehorse to Tuktoyaktuk, lakes in the Yellowknife region, the Belcher Islands, Labrador, and throughout the high Arctic, such as Ellesmere Island and Greenland. Complementary studies from Lapland and Siberia have also been undertaken, with comparative studies from Antarctica and Alaska are being planned. From these calibration studies, transfer functions are developed, which we then use for our paleoecological studies.

Using the above quantitative transfer functions, PEARL scientists are using lake, pond, river, and bog sediments to examine many environmental problems. For example, the lab headed the USEPA's Paleoecological Investigations of Recent Lake Acidification (PIRLA) research. These data were required to determine if in fact lakes were acidifying, how many were affected, and are they still acidifying. PEARL continues its involvement with the USEPA by coordinating the diatom paleolimnology portion (by Dr Sushil Dixit) of their new Environmental Monitoring and Assessment Program (EMAP). Lake acidification and fisheries losses are also studied in Ontario using paleoecological techniques. Natural and anthropogenic lake eutrophication trajectories is another area of active research, as is the use of lake sediments to decipher the history of contaminants.

A large portion of the lab's research has recently focused on studies of environmental change in the Arctic. PEARL is studying lake processes throughout the Canadian, Greenland, Scandinavian, and Siberian Arctic. Much of this research is studying long-term environmental change, and contrasting natural changes to those induced by anthropogenic activity, such as from contaminants. Other projects focus on the study of long-term climatic change. Paleolimnology has much to offer paleoclimatic studies.

PEARL scientists are also actively involved in the description of new indicator groups. For example, in 1995, we published the Atlas of Chrysophycean Cysts (Duff, Zeeb and Smol, Kluwer Academic Publishers, The Netherlands). This atlas documents the taxonomy and ecology of this relatively underutilized indicator group. Additional books on, for example, diatom floras, have also been published, and other projects are underway.

PEARL also hosts several workshops each year, mostly dealing with diatom taxonomy, ecology, and data management.

If anyone wishes to receive further information on any of these topics, please contact Dr John Smol, Paleoecological Environmental Assessment and Research Lab (PEARL), Queen's University, Department of Biology, Kingston, Ontario, K7L 3N6, Canada. Tel: (613) 545-6147, Fax: (613) 545-6617

For more information, see also the PEARL website: http://darwin.biology.queensu.ca/~pearl/

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Note: This article first appeared in CAP Newsletter 15(2):16-17, 1992. Updated 14/11/99.