News & Events

Noon seminar - Molluscan sclerochronology and its potential for paleoclimate reconstructions in the

Monday, October 08, 2018, 12:15PM - 1:15PM

Speaker

Fabian Bonitz

Norwegian Research Centre and Bjerknes Centre for Climate Research, Bergen

Location:

SEEC room S228 (Sievers Room)

Full title

Molluscan sclerochronology and its potential for paleoclimate reconstructions in the North Atlantic

Abstract

Highly-resolved and precisely-dated proxy-archives in the marine realm are scarce, especially at high latitudes, but urgently needed to better understand the natural climate variability and its impacts on marine ecosystems over the last millennium. In this context, it is fundamental to obtain well-constrained information about natural trends, cycles and potential feedback mechanisms, as well as the magnitude and rate of natural changes. This can help to better estimate the anthropogenic influence and put the observed recent changes into perspective.

A promising high-resolution proxy-archive for the northern North Atlantic is provided by the shell properties of the mollusc Arctica islandica. This bivalve species forms annual growth lines and increments, which can be analyzed similarly to tree rings. By cross-matching growth increment patterns of live-collected and sub-fossil specimens, long, annually-resolved, and absolutely-dated master chronologies can be constructed. Since the shell growth is mainly driven by food availability and temperature, the shell growth variability can provide information about past climatic and environmental conditions. In addition, geochemical properties of A. islandica shells, such as the stable isotope (d18O and d13C) composition, can be used to reconstruct past changes in temperatures and bioproductivity.

For this seminar, the potential of the field molluscan sclerochronology for paleoclimate reconstructions is presented with special emphasis on results from the Faroe Island region.

Audience

Free and open to the public.