Seasonal Diatom Variability and Paleolimnological Inferences – A Case Study |
| |
| Authors: | Dörte Köster Reinhard Pienitz |
| |
| Institution: | (1) WATER LAB, Department of Biology, University of Waterloo, N2L 3G1 Waterloo, Ontario, Canada;(2) Paleolimnology–Paleoecology Laboratory, Centre d’études nordiques, Département de Géographie, Université Laval, G1K 7P4 Québec, Canada |
| |
| Abstract: | The seasonality of physical, chemical, and biological water variables is a major characteristic of temperate, dimictic lakes.
Yet, few investigations have considered the potential information that is encoded in seasonal dynamics with respect to the
paleolimnological record. We used a one-year sequence of diatoms obtained from sediment traps and water samples, as well as
the sedimentary diatom record covering the past ca. 1000 years in Bates Pond, Connecticut (USA), to investigate which variables
influence the seasonal distribution of diatoms and how this can be used for the interpretation of the fossil record. The seasonal
patterns in diatom assemblages were related to stratification and, to a lesser extent, to nitrate, silica, and phosphorus.
During mixing periods in spring and autumn, both planktonic and benthic species were collected in the traps, while few lightly
silicified, spindle-shaped planktonic diatoms dominated during thermal stratification in summer. Changes in fossil diatom
assemblages reflected human activity in the watershed after European settlement and subsequent recovery in the 20th century.
A long-term trend in diatom assemblage change initiated before European settlement was probably related to increased length
of mixing periods during the Little Ice Age, indicated by the increase of taxa that presently grow during mixing periods and
by application of a preliminary seasonal temperature model. We argue that the analysis of seasonal diatom dynamics in temperate
lakes may provide important information for the refinement of paleolimnological interpretations. However, investigations of
several lakes and years would be desirable in order to establish a more robust seasonal data set for the enhancement of paleolimnological
interpretations. |
| |
| Keywords: | Connecticut Diatoms Lake Mixing Quantitative inferences Seasonal succession Sediment trap |
| 本文献已被 SpringerLink 等数据库收录！ |
|
