manuscript\variab1.doc Oct. 1998 WHEN DOES ENVIRONMENTAL VARIABILITY BECOME ENVIRONMENTAL CHANGE? THE PROXY RECORD OF BENTHIC FORAMINIFERA

There are three possible approaches to investigating environmental change using organisms as proxies: comparison of spatial surveys from different time periods, timeseries studies, and high resolution studies of cores. Because they have a preservable shell and are abundant, benthic foraminifera are the best meiofaunal group for giving a proxy record of past marine and marginal marine environments. Through the analysis of: changes in abundance of marker species; the introduction of new species or serious loss of previously existing species; changes in species diversity, dominance and abundance which extend well outside the established limits of variability; it is possible to document the extent of environmental changes that have taken (or are taking) place.