Laci M. Gerhart Barley

Home » Continental Wood Nitrogen » Continental N Rises Again!

Continental N Rises Again!

At least until June 12th, no one will be telling me I’m not in Kansas anymore, because I’m back in Kansas!

Kendra and I were successful with our small grant proposal to NSF for the wood stable nitrogen isotope project (nicknamed ‘Continental N’), which means that we can now actually analyze all those samples Emily and I collected over spring break! I got back to the Paleoenvironmental Lab on May 11th to get the ball rolling and tie up all the loose ends.

0518151659a

There were a lot of loose ends

Goals:
1) Weigh all the backlogged samples for analysis: All the spring break cores (and others that were mailed in over the last year) have been processed and split. Now we need to weigh out the appropriate amount of tissue (~30 mg) and wrap it in tin for the mass spectrometer to burn up.

2) Herd up the stragglers: there are still a few sites that need to be sampled. And a few that need to be re-sampled because the initial cores we collected were too short for our purposes.

3) The analytical questions: in the grant, we also wrote in a couple strategies for testing analytical fidelity in wood nitrogen measurements. These are nicknamed the replication tests.

So, two weeks in, where do we stand?

Goal 1: Weigh the backlog

0521151618

This empty shelf makes me very happy

DONE! With the help of Allison Walker (new undergrad in the lab) and Kevin Courtois (whose wife is a post-doc with Kendra), we got through the ENTIRE BACKLOG of to-be-weighed samples in half the expected time. I am absolutely ecstatic about the progress on this front. There will be more to weigh as we process incoming samples, but keeping up is much easier when you don’t have ~20 sites worth of trees already waiting.

Today, I mailed over 2,000 samples to the University of New Mexico’s stable isotope facility. We’ll hopefully start getting data back on these sites before I get back to Hawai’i. My R code is ready and waiting 🙂

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Good luck, little samples!

Goal 2: Herd the stragglers

We’re making impressive progress on this front, too. 0522151436We have four sites that have been sampled and mailed to us and are awaiting processing: Hoh Forest (Washington), Grand Tetons (Wyoming), Salmon River (Oregon), and Wedington Gap (Arkansas). We also have colleagues sampling in Illinois, New York, Utah, and Nevada in the next week. I’m working on permitting for Pennsylvania, and we’re waiting to hear back from colleagues on a couple other locations, but we’re nearing the end of our sampling stage.

Our completion of the backlog means I can devote my entire attention to processing these cores and getting them mailed off before I leave Kansas. For now, they are drying in the oven, but after Memorial Day, I’ll start cranking through them.

Goal 3: The replication tests

We’re also planning to test the replicability of wood nitrogen measurements by sending homogenized, ground sawdust samples to various isotope labs across the U.S. and Europe and assessing the fidelity between the measurements. Currently, there are neither formal standards for wood nitrogen analysis, nor a standardized equipment protocol. We plan to use these tests and the in-house protocols to develop recommendations for standardizing wood N analysis, and potentially petition the National Institute of Standards and Technology (NIST) for a formal wood stable nitrogen isotope standard.

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The replication test wood

Check back here to see how we progress before I head back to Hawai’i!!

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