Postdoc 2009: Nathalie van der Putten

Can you give some brief information about your research?

As instrumental and historical records of past climate only span the last few centuries, we need natural archives to reconstruct climate change beyond that period. Such natural archives can be found in ice caps, deep-sea sediments and terrestrial deposits and specific proxy-methods exist to investigate each of these past climate archives.

My research focuses on terrestrial deposits, and more specifically on peat deposits originating from sub-Antarctic Islands. The oceanic, cool climate with high precipitation all year round, is highly favourable for the formation of peat deposits on these islands. Sub-Antarctic islands are characterised by a tree-less vegetation with a low number of flowering plants. Mosses are a major component in all plant associations.

Within this post doc, previously almost unexplored records in peat bogs, covering the last c. 20000 years, from the Iles Kerguelen archipelago (South Indian Ocean ) will be analysed, using a multi-proxy approach.

The main proxy-method will be plant macrofossil analysis in order to reconstruct the evolution of the local mire vegetation in time. Plants, in this case mainly mosses, living in peat lands are sensitive to changes in mire hydrology, therefore changes in species assemblages can be used to infer periods of climate change, especially atmospheric changes.

Magnetic susceptibility and XRF measurements, geochemical analysis of the organic matter and mineral grain analysis can be used as proxies for in-wash, eolian influx, diagenetic changes and tephra deposition.

The records will be thoroughly 14C-dated and investigated on a high resolution in order to be able to correlate them with continental, marine and ice-core records from both the Southern and the Northern Hemispheres.

Where will you have your postdoctoral post in Sweden and why?

I will have the possibility to apply plant macrofossil analysis on some of these well-dated peat sequences of South Atlantic Ocean islands (NightingaleIsland and Isla de los Estados). In this way, I will gain experience in the palaeoecology of more temperate island systems.

In addition and very important, comparisons and correlations to the Lund-based South Atlantic peat and lake sites, as well as their numerous Antarctic records, are critical to understand large-scale latitudinal shifts and/or strengthening of the Southern Hemisphere westerlies, and how they have interplayed with the global climate system.

What does this mean to you?

I will get acquainted with new scientific skills and will be able to discuss the results with experienced researchers working in my research area. I also will widen my research network considerably.

As I already experienced during a two year stay at a French laboratory (IMEP, Marseille), a stay at a university in a foreign country is always an enrichment, both from a scientific as a personal point of view. I am looking forward to move to Sweden soon.