Field Sampling

One of the best part of biogeochemical research is getting out into the field. First of all, seeing the research site set within the landscape gives context and relevance to the project and the expected outcomes. Second of all, excursions into the field expose the non-natives (us) to the communities that work close to the land and resources that we study. When we are really lucky, we can take part in the fruit of the land. We are lucky to have a local apple press near by our study pot-holes (small water bodies). The owner is quite eccentric, but his group makes juice and apple cider wine (even a sekt) from local orchards. 

Amazingly, the owner didn't reference certain orchards when we talked about which apples were used, but individual trees! The taste is unique, very earthy, and takes a sip or two to get used to, but I think it would be welcomed at any table up here in NE Germany during the dark winter, crisp spring air, or the still summer.

Apples ascending the press-belt

Ecological Society Meeting in Potsdam

This week the Ecological Society of Germany, Austria and Switzerland is holding a meeting in Potsdam. Kai Nitzsche, PhD candidate, is presenting his poster on kettle holes (pot holes if you are from North America) dispersed across the agricultural landscape of NE Germany. He will perform some very cool experiments regarding priming of organic matter in soil and sediments, and water flow into these small water bodies.  Here is his poster he will present, (click on it for the pdf):

Adam Roddy will also present a talk about his work in Southern Germany investigating isotopic non-steady-state of leaf water.

Canopy position influences the deviation of 

plant-transpired water vapor from isotopic steady-state

If you are lucky enough  to be there, then don't miss these presentation opportunities! 

Isotope Seminar in Slovenia Forestry Institute 

I was recently in Ljubljana to help give a seminar on stable isotope applications in forest research. There is quite a lot of ground to cover for such a course, but one week was sufficient for the Slovenian post-docs and PhD students. 

We also went to their field site where they maintain two eddy-covariance towers. They compare the two towers, one in the open grassland and the other in a sparse woody landscape, to get a handle on woody encroachment. This site is particularly special because not only is there the non-homogenous canopy to deal with (reminiscent of the California Foothills) .....

but also these sink holes. 

These are dotted across the landscape and can be easily seen from satellite imagery. The locals have actually surrounded the edges with limestone so they show up even clearer in the picture. In the past, Slovenians would plant gardens in the sinkholes because they are more fertile and have a deeper soil layer. Clearly these are hotspots of biogeochemistry and could play an important role in the landscape.

I had a good time overall and I was able to see a few uniquely Slovenian creations:

A Shepard's temporary home

And these hand sewn/crafted trees displayed in the SFI's main building. I can't imagine the amount of time and skill it took to craft the forest they house. 

Live, from the Ecotron! 

For the next couple of weeks I am in Montpellier, France working at the amazing CNRS Ecotron facility. The project stems from a collaboration of many european partners who are interested in circadian rhythms of ecosystem fluxes. Hopefully, our experiments will improve the basic understanding of how plant and soil CO2 and water fluxes are regulated, thus improving general ecosystem models. It is also fun to think about how ecosystems rely on internal time cycles to function- is there a competitive advantage? Can we see this expressed at the gene and RNA level? Do soil microbes synchronize their clocks to the dominant vegetation? Maybe these are the next questions to answer.

As you can see in the pictures below the Ecotron allows you to monitor entire intact monoliths removed from the field in isolated chambers-with replicates! Below, the monoliths are placed on lysimeters allowing for a pretty tight water balance, and of course, the data are collected continuously. It doesn't hurt that the facility is located within a beautiful landscape in a region where great food and wine are all around! 

My 4am to 5pm shifts at the LiCor have just ended so I look forward to a bit of rest, then I will take a look at some of the data, of which there are plenty, in the coming days.    

New paper in review at Biogeosciences Discussion!

This paper is part of Katrin Attermeyer's PhD work at IGB. She added carbon from extracted algae to carbon from labeled beech leaves. Turns out the microbes loved it!

New Proposal Submitted!!

After considerable blood, sweat and tears had been spilled, I submitted a new proposal to the DFG Biodiversity Exploratories! My Co-PI's and I will investigate the relationship between soil respiration and biodiversity. When it is successful I will give more details, but in the meantime these word clouds give some indication... ..

Tapping into tree phloem.

Recently, I was at the MPI-Jena helping Claudia Winters, Gerd Gleixner and his PhD student, Ronny. We were exploring different techniques to sample phloem on-line followed by isotopic analysis of the samples by LC-IRMS. The temporal dynamics between canopy physiology and belowground respiration as mediated by phloem transport remains a mystery. Isotopic techniques[1], statistical investigations [2], and modeling [3] have been employed to tease out the canopy-phloem-rhizosphere connection; I had a short letter regarding these approaches. In the meantime, we are still waiting for direct measurements that can be sampled over the day......

Footnotes:

1. Brüggemann et al., 2011

2.Vargas et al., 2010

3. Mencuccini and Hölttä, 2009 

You can also see  Kayler et al., 2010 for a brief discussion of phloem transport and canopy-soil interactions.