The Twelfth International Diatom Symposium stressed how diatoms can be used to assess the human impact on natural waters, without neglecting other important fields of research. As the frustules of many diatom species are relatively resistant to dissolution they are preserved in freshwater and marine sediments and provide a record of past environments on earth. In past decades they have been successfully used to reconstruct changes in water bodies evoked by changes in salinity, acidification and eutrophication. In the last few years diatom-inferred predictions of environmental variables have become much more quantitative. In the most recent research reports the strong separation between palaeolimnological and neolimnological diatom research is fading, as palaeolimnologists are increasingly using modern calibration sets to infer past states of the environment. This quantitative approach is also very suitable for prediction of future changes in the biota of surface waters. Also ecological changes due to climatic modification have been investigated more thoroughly recently. A very important new research topic is the occurrence of toxic diatoms, particularly along the coasts of North America. These proceedings are intended to be a balanced view of such modern developments in diatom research. They should also be of interest to non-specialists in diatoms, who can use the results of diatom research as a tool in a more general taxonomic, ecological and geological context.

Future impacts from climate change can be better understood by placing modern climate trends into perspective through extension of the short instrumental records of climate variability. This is especially true for extreme climatic events, such as extreme precipitation and wildfires, as the period of instrumental records provides only a few examples and these have likely have been influenced by anthropogenic warming. Multi-parameter records showing the past range of climate variability can be obtained from lakes. Lakes are particularly good recorders of climate variability because sediment from the surrounding environment accumulates in lakes, making them sensitive recorders of climate variability and providing high-resolution histories of local environmental conditions in the past. In some cases, such as at Basin Pond, sediment is persevered efficiently enough to produce distinguishable annual laminations (varves) in the sedimentary record. The varved record at Basin Pond was used to construct an accurate, highly-resolved age-to-depth model over the past 300 years. Using a multi-proxy analysis, including organic biomarker analysis of molecular compounds and sedimentological features preserved in the sediment record, a history of environmental and climatic change at Basin Pond was constructed. These analyses were compared with the record of known extreme events (from instrumental measurements and historical documents), including 129 years of high-resolution precipitation and temperature meteorological data, 19 tropical systems over the past 145 years, and two known wildfire events over the past 200 years. Long-term trends in precipitation, including the increase in precipitation seen throughout the last half of the 20th century and the drought of the 1940's, were captured in the analysis of long-chain n-alkane distributions and through varve thickness measurements obtained through X-Ray Fluorescence analysis. Furthermore, Polycyclic Aromatic Hydrocarbons (PAHs), a class of organic compounds that can be used to trace combustion activity, were found in abundance in the Basin Pond sedimentary record. Peaks in the abundances of two PAHs (retene and chrysene) and the ratio retene/(retene + chrysene) were found to be highly correlated with the known wildfire events occurring in the historical period, giving promise as using these compounds and ratio as a robust proxy for regional wildfire events in the northeastern U.S.

Paleoclimatology: Reconstructing Climates of the Quaternary, Third Edition—winner of a 2015 Textbook Excellence Award (Texty) from The Text and Academic Authors Association—provides a thorough overview of the methods of paleoclimatic reconstruction and of the historical changes in climate during the past three million years. This thoroughly updated and revised edition systematically examines each type of proxy and elucidates the major attributes and the limitations of each. Paleoclimatology, Third Edition provides necessary context for those interested in understanding climate changes at present and how current trends in climate compare with changes that have occurred in the past. The text is richly illustrated and includes an extensive bibliography for further research. Winner of a 2015 Texty Award from the Text and Academic Authors Association A comprehensive overview of the methods of paleoclimate reconstruction, and the record of past changes in climate during the last ~3 million years Addresses all the techniques used in paleoclimatic reconstruction from climate proxies With full-color throughout, and thoroughly revised chapters on dating methods, climate forcing, ice cores, marine sediments, pollen analysis, dendroclimatology, and historical records Includes new chapters on speleothems, loess, and lake sediments More than 1,000 new references and 190 new figures Essential reading for those interested in how present trends in climate compare with changes that have occurred in the past

Raymond S. Bradley provides his readers with a comprehensive and up-to-date review of all of the important methods used in paleoclimatic reconstruction, dating and paleoclimate modeling. Two comprehensive chapters on dating methods provide the foundation for all paleoclimatic studies and are followed by up-to-date coverage of ice core research, continental geological and biological records, pollen analysis, radiocarbon dating, tree rings and historical records. New methods using alkenones in marine sediments and coral studies are also described. Paleoclimatology, Second Edition, is an essential textbook for advanced undergraduate and postgraduate students studying climatology, paleoclimatology and paleooceanography worldwide, as well as a valuable reference for lecturers and researchers, appealing to archaeologists and scientists interested in environmental change. * Contains two up-to-date chapters on dating methods* Consists of the latest coverage of ice core research, marine sediment and coral studies, continental geological and biological records, pollen analysis, tree rings, and historical records* Describes the newest methods using alkenones in marine sediments and long continental pollen records* Addresses all important methods used in paleoclimatic reconstruction* Includes an extensive chapter on the use of models in paleoclimatology* Extensive and up-to-date bibliography* Illustrated with numerous comprehensive figure captions

Annual meeting for held jointly with the Minnesota Academy of Science.

Surveys atmospheric, oceanic and cryospheric processes, present and past conditions, and changes in polar environments.