ABSTRACT: Diatoms and silicoflagellates as indicators of Holocene climate trends in Saanich Inlet, British Columbia, Canada

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

Diatom history and climate change in Saanich Inlet can be studied in great detail over the last 12,000 years because its laminated sediments are easily sampled at annual and sub-annual levels. Short, frozen sediment cores provide a record of seasonal diatom changes over the last 100 years, a record which is similar to species successions observed in the inlet today. Interannual changes in diatom abundance are observed on a decadal scale, a trend also found in fish catch records and sea surface properties in other areas of the northeast Pacific. Longer timescale variations are being examined from 100 m long cores taken by ODP Leg 169S. Results suggest that species composition and abundance in the long cores is similar to the frozen cores as well as recentphytoplankton samples. The total number of diatoms per gram sediment fluctuates along the length of the core with years of high concentration (125 million/g) occurring every 600-700 years. Paralia sulcata is very rare in samples below 35 m. Although the diameter of this species has been associated with changes in temperature and salinity, there is no obvious difference between valve widths of Paralia above and below 35 m. This may partly be due to a lack of Paralia cells deep in the core. A period of high silicoflagellate abundance occurs early in the Holocene and may be due in part to an unusual flood event at this time. A database of phytoplankton and environmental data is being compiled to better understand the ecology of individual phytoplankton species in Saanich Inlet and surrounding waters. These data provide the basis for transfer functions which will be used with fossil records to estimate past changes in climatic parameters such as salinity and temperature

Bibliography of Canadian Geomorphology