Dead heads

July 30, 2013
encarnimontoya

DeadHeads12th International Workshop on Subfossils Chironomids
10-13th June, New Forest, UK

Last month Frazer and Encarni attended the 3-days “dead heads” workshop that was held at the Beaulieu Hotel , in the New Forest National Park (UK). It was perfectly organised by Pete Langdon and Steve Brooks,  and was a great opportunity for both of us who are relatively new to the midges’ community. With around 40 participants from Europe, America and Asia, we greatly enjoyed the discussions that came up about the state-of-the-art for this interesting proxy and the implications for palaeoclimatology, palaeolimnology, and different aspects of ecology like conservation, restoration or community assemblages. In addition, useful topics such as current methodological problems with age-depth model uncertainties, the usefulness and limitations of transfer functions, and taxonomy were also debated.

Besides oral and poster presentations, the workshop offered several tutorials during the afternoons, key amoung these were an introduction to R carried out by Richard Telford and Steve Juggins, and taxonomic support for head capsules ID leaded by Steve Brooks and Oliver Heiri.

In our specific case, Frazer contributed with an oral presentation titled Understanding the modern distributions and ecological tolerances of the Neotropical Chironomidae fauna: The potential as a palaeoecological proxy” base on his PhD research. We were both so glad to make contact with other people working in South America, in particular Julieta Massaferro and Alberto Araneda presented very interesting data from Argentina and Chile.

Although these meetings are normally biannual, next conference location and date is yet to be decided, but we hope to have the chance to join this very friendly and supporting community again. We encourage people with all kind of experience (or lack of) to attend any further events.

Lake coring equipment

July 17, 2013
WDG

Trecking with sediment corer in the high Andes of Peru

Trecking with sediment corer in the high Andes of Peru

When it comes to collecting sediments from lakes its all about having the right tools for the job. Working in remote areas of the tropics we tend to favour the Colinvaux-Vohnout corer; supplied by Vince Vohnout at Geo-core). The advantages of this system are:

  1. its light-weight nature (can be backpacked or donkeyed into field sites), and 
  2. the cam system (which allows hammering to penetrate tough sediments).

    Eric Martinez carrying an Avon Redstart back out from Laguna Khomer Kotcha (Williams et al., 2011)

    Eric Martinez carrying an Avon Redstart back out from Laguna Khomer Kotcha (Williams et al., 2011a)

With the right platform (two banana boats and an A-frame) we have manged to retrive c. 20 m of sediment from  20 m of water (c. 40 m of drill rod extended); Lake Pacucha, Peru (Hillyer et al., 2009). More typically we use two Avon Redstart inflatables and a platform following the design of Colinvaux et al. (1999).

Recent debate on the International Paleolimnology Association list server saw recommendations for a number of other systems.

Including: UWITECH gravity corer, Pylonex gravity corer, Aquatic Research Instrument products, and modified systems by Jason Curtis at University of Florida.

I would be interested if anyone has any thoughts on the relative merits of these systems (or others) and there capabilities.

Photos and references below:

Continue Reading

Blog at WordPress.com.