Land-Use and Climate Changes during the Irish Bronze Age: What can the Nitrogen Cycle Tell Us?

Description

Isotope zooarchaeological research in Ireland has identified a sustained positive shift in the nitrogen stable isotopic values of faunal remains during the Middle to Late Bronze Age (1750-800 BCE). This has been hypothesised to have been triggered by an intensification of farming, representing a potential indelible human footprint in the Irish geologic record (Guiry et al., 2018, Science Advances). However, whether these region-wide changes were triggered by anthropogenic factors or by natural climatic changes has not yet been tested.
This paper will present preliminary results from a multi-proxy analysis of sedimentary records that seeks to establish whether a region-wide N isotope change was triggered by human activity or climate. Ombrotrophic peat bogs obtain their nutrients from the atmosphere, meaning their stable isotopic values should reflect climatic fluctuations, unlike lake sediments, which should reflect both climate and land-use changes. In addition to carbon and nitrogen stable isotope measurements, pollen and testate amoebae analyses are also used to reconstruct land-use, bog surface wetness and water-table fluctuations. Through this multi-proxy study, we explore the inter-relationships between the nitrogen cycle, climate and human activity and consider whether there is a case for an early Anthropocene in Ireland.

Period	25 Mar 2023
Held at	IQUA, Ireland
Degree of Recognition	National