Development of an intertidal foraminifera training set for the North Sea and an assessment of its application for Holocene sea-level reconstructions

Regional datasets of the vertical distribution of intertidal foraminifera are useful to reconstruct Holocene sealevel changes from fossil foraminifera in estuaries and salt marshes. In this paper, we present a new foraminiferal dataset from the Ythan Estuary (Scotland) and combine it with data from eight other coastal sites from England, Denmark and Germany to produce a regional modern training set for the North Sea. We recognise a correlation between foraminifera and tidal elevation which makes the foraminifera suitable as sea-level indicators. We subdivide the data into subregional training sets and develop WA and WAPLS transfer functions. Applying a variety of statistical methods, including detrended canonical analysis, cross-validation by bootstrapping and leave-one-site-out, and the modern analogue technique, we establish the most appropriate transfer function from which to reconstruct early Holocene sea-level changes in a sediment core from the western North Sea coast. Results show that the subregional England/Scotland training set provides the most appropriate sealevel reconstructions, with decimetre-scale uncertainties. The techniques we use in this study, that consider both the modern and fossil assemblages to determine the best training set and transfer function, are suggested as a template for the development of regional transfer functions based on foraminifera and other intertidal microfossils.

Automated summary

This study utilizes regional modern training sets and transfer functions based on foraminifera to reconstruct early Holocene sea-level changes. By employing various statistical methods and data processing techniques, the study establishes suitable sea-level indicators and transfer functions.