Laboratory activity has continued through February with progress on pollen counts (Lottie and Hayley) and chironomid (non-biting midges) picking (Frazer). Hayley also managed to escape the microscope lab for a short period: 1) to commence work on selecting samples from tephras for Ar-Ar dating, and 2) to counduct loss-on-ignition analysis of organic samples to identify the constituents of her sediment. I did not make it on to the microscope 😦
I was however very pleased to welcome Macarena Cardenas back into the lab as a visiting Research Fellow. Maca will be working on the pollen reference collection, assisting with PhD student analysis and continuing to write papers during her renewed association.
Frazer, Hayley and I have also begun planning for field work in Ecuador for April-May. We will be working in collaboration with the Instituto Geophisico in Quito and the plan is to visit the Mera site which Hayley is working on, and to collect lake surface samples for Frazer to examine the midges. In preparation for the collection of midges samples expert, and project co-supervisor, Steve Brooks (Natural History Museum) visited for a day to brief us on how best to do this.
Away from research I have been working on writing exam questions and tutor marked assignments for the level 3 module The geological record of environmental change (S369, to those familliar with OU codes!). Hopefully, I have managed to set some interesting and challenging tasks for our students. . .
For the third year running a team of palaeoecologists took part. This year “Team Palaeo” comprised Hayley Keen, myself, Frazer Bird and Lottie Miller (left to right on photo) and we were the fastest finishing team from the department!
COMMENT ON THE USE OF NITROGEN ISOTOPES IN PALAEOLIMOLOGICAL STUDIES As a component of my doctoral research, I am examining nitrogen (N) isotopes within sediments obtained from Lake Bosumtwi (West Africa). Below I review and comment on the key uses and limitations of using N isotopes to interpret past environmental change with particular reference to lake sediments. Discussion is based on the key text by Talbot (2001).
Talbot, M.R. 2001. Nitrogen isotopes in palaeolimnology. Tracking environmental change using lake sediments. Volume 2. Physical and geochemical methods (ed. by W.M. Last and J.P. Smol), pp. 401-439. Kluwer Academic Press, Dordrecht.
COMMENT ON DISCUSSION OF PROXIES IN HUNTLEY (2012) All areas of research have strengths and limitations which are readily acknowledged by the scientists involved. The reconstruction of past climates (palaeoclimates) from biological indicators contained within the fossil record (proxies) presents some specific challenges; for example key limitations might be gaps in a sedimentary sequence or post-depositional degradation of samples. Understanding and interpreting data sets in the face of these challenges require the researcher to develop a wide range of skills. Huntley (2012) focuses upon the uncertainties within palaeoclimate reconstruction which he considers to be “frequently overlooked” (p. 2) by scientists making climate reconstructions from proxy records. Specifically Huntley urges researchers to consider carefully:
What a given proxy is actually capable of reconstructing, i.e. what climate variables controls its distribution?
What other variables might be influencing the proxy, i.e. could there be multiple influences, might these vary through time?
What is the spatial relevance of the proxy, i.e. macro versus micro scale?
Can multiple proxies be compared, either within or between sites?
In other words: which and how many climatic variables can be reconstructed form any one aspect of the fossil record?
Below I review and comment on some key arguments made by Huntley (2012) related to the use of proxies in reconstructing palaeoclimates.
January 2012 has been a busy one for the Palaeoenvironmental Change Research Group members we have been getting out and about (attending three research meetings), there has been activity in the labs (pollen, chironomids and geochemical analysis all being undertaken) and developments with the publication of our research (book chapter published and two papers moved along in the publication process).