Salt marshes as archives of recent relative sea level change in West Greenland

Abstract

Temperate latitude salt marshes are a proven environment from which high precision (±0.10–0.20 m) relative sea level (RSL) records can be developed over recent decades and centuries. Such records provide an important link between millennial histories of RSL change and instrumental records. The high latitude salt marshes in Greenland have not previously been explored as potential archives of recent RSL change. Here we develop four diatom-based transfer functions using contemporary diatom data collected from three salt marshes located 40 km south of the coastal town of Sisimiut, West Greenland. Our preferred model has a good fit between observed and predicted elevations ( r 2 = 0.94) and a root mean square error prediction of ±0.19 m. We apply the four models to a short sediment profile collected from one of the marshes that formed between c. 600 cal. year BP and the present. Three of the four models predict the same trend in which RSL rose from −0.55 ±0.19 m mean tide level (MTL) to −0.05 ± 0.19 m MTL between c. 600 and 400 cal. year BP at a rate of c. 2.7 mm year −1. After 400 cal. year BP RSL slowed and remained stable until the present day. The results of this study demonstrate that Greenland salt marshes are potentially valuable archives of data for developing quantitative estimates of RSL change during the last few centuries, thereby bridging the gap between existing millennial-scale approaches and more recent direct observations of ice sheet behaviour and associated vertical land motions.