Tips for Taking Off Your Gloves

Did you know that our hands have a lot of sodium on them, and the leaf samples we are studying have very little? The 2016 Fall Litter Samples are being chemically analyzed, therefore we are wearing gloves when dealing with these samples so as not to contaminate them. It’s important to wear gloves and when putting on, wearing, and taking off the gloves to not touch the outside of them. Using the method described in the video you can take off your gloves if necessary and be able to put the same gloves back on without contaminating the outside of the gloves or needing to get a new pair.    –Maria Scheibel

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Sorting 2016 leaf litter has begun!

The 2016 Leaf Litter is going to be handled differently from previous years.  Nat, Maddy, Cindy, Melany, Gretchen, Dan, Ryan, Adam, Grace, and Maddy (again) collected litter four (4, count them) times this fall:  Oct 7-9, Oct 17-18, Oct 21-23, and Nov 4-6.  This means that Melany’s crew in Ohio can get nutrient contents (as in 2012, which was also collected 4 times (better for nutrient analysis than letting them sit in baskets all fall starting to decompose).  It also means that we can look at whether our N and P treatments affect the rate of leaf fall (Griffin is working on this).  And Dan and Gretchen are comparing litter nutrient concentrations to the green leaves they shot in August, to study nutrient translocation.

Most of these samples do not require sorting, but:

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We are going to analyze leaf litter by species, which requires sorting, in C1 and C9 control plots, which will contribute to a paper by Craig, Tim, and Ruth that shows how N and P decline over the course of the fall.  We will also use this time series to evaluate the “fresh” litter samples that Dan and Gretchen collected in the pouring rain on Oct 21-23.

Here is Phuong teaching species ID to Alex, our newest lab member and a grad student.

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Here is an important question for our collaborators. What should we do with the “non-leaf” material?  When we sort, we don’t include this, but for all the stands where we are not sorting, these would be ground along with the leaves and analyzed!  So far, we have found a red-backed salamander, a worm, and an unknown insect pupa (can  anyone ID?), and two millipedes!

 

 

Here is another important methodological question. For all the bags that got crushed, ground, and are being ashed and digested for nutrient analysis, we analyze everything in the bag. However, for the samples we are sorting and analyzing by species, should yucky leaves from the wet corner of a basket (below) be included with the species samples?  One idea is to put them with the “unknown” species crumbles. Everything will be weighed, composited, and analyzed; including the unknowns, so that we also get total nutrient flux in the baskets.

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Until you are 18, you can’t grind, ash, or digest samples, but some of you can do this and we’ll post pictures for the rest of you!

 

 

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Useful for Reuse!!

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Say goodbye to clutter! These litter collection bags are packed, clipped, and ready for action in the 2017 field season.  They are already labeled by stand, plot, and basket.

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Our very own Grace Lockwood has done an exceptional job double checking the Spring and Summer litter from 2015 and 2016.  We don’t need to keep these (the attic is filling up with the more valuable Fall litter collections) so she dumps them into a garbage bag after looking for non-leaf material and counting cherry pedicels, birch catkins and bracts, and today only, a red spruce cone.  We thought she was all done, and we had a bonfire to burn the samples and celebrate Yang Yang’s PhD candidacy exam.  But it turned out there were more samples hiding…  We will have another bonfire to celebrate Kara’s thesis defense, hopefully on December 19.

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Rescued from Oblivion

Last weekend DeZhane noticed that the sharpie was rubbing off the ziplock bags of the litter from trip 3 2016. To prevent losing the identity of the samples,  we printed  labels to place into the bags. Now the samples really know who they are. #nomoresoulsearching

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Blast from the past!

Now that we’ve finished all of the 2015 leaf litter samples and have our 2016 samples underway… we can work on soil samples again! We haven’t sorted roots in a long time.

Maria, one of our newest high school students, is working on a BEF 2015 soil sample.

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After picking out the roots, they’re placed in a bowl of water to clean off soil.

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Then, roots are sorted by size class. We use a caliper to measure the diameter of the roots.

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This was a pretty big sample, so it’s going to take a couple more people to finish picking out roots.

Stay tuned to see what happens next time!

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Paper or Plastic?

11/19/2016:

Fall 2016 Leaf litter was collected 4 times so that Melany Fisk could analyze nutrient concentrations.  Dry litter can be collected in paper bags.  But wet paper  bags can break and lose our samples.  It was pouring rain on the 3rd collection date, so those samples were collected in plastic.  For those of you who have been spending time trying to sort leaves that were collected very dry, these look easy to work with!  20161119_123827

Some of the samples are so wet, you can see the dissolved organic carbon that leached out.     We were concerned about transferring these to paper bags to dry.img_1904

Trial and error has led to the development of procedures for drying in plastic, which will save time and the possibility of labeling errors. Permanent marker tends not to be so permanent on plastic, making the bag labels sometimes hard to read.  To solve this problem, we printed labels and placed them inside the bag with the sample.

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Plastic bags don’t wick water like paper and therefore drying the samples can be a challenge.  If the plastic bags fall over and close, they tend not to dry.  The proper drying of samples in plastic involves arranging them in rows with the the rim of the individual bags folded over to ensure that the bags stay up right and open to allow airflow while drying.

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The bags are placed in a box, which also helps to minimize the time needed to place them in the oven.  If the oven is open too long and cools off, it can overshoot our target temperature when it heats up again.

We tested both types of plastic bag overnight before we put any samples in the oven.  We didn’t want melted plastic and lost samples!

Gretchen will be stopping in twice this week to weigh bags and determine how long it takes to dry them in plastic.  Which is better, paper or plastic?  Stay tuned.

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Sample clones and oven mysteries

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Today we started out by investigating the effects of a mysterious dip in the drying oven’s temperature down to 48 C. To check to see if this would affect our data, Nick weighed a few samples and weighed them again when they got to 60 C. The differences were 0.5% – 1.5% of the mass, so we determined this to be ultimately insignificant.

While working we uncovered a cadre of copycat samples (Griffin says its more like identity theft than copycatting), with labels that have already been entered into our data sheet! These samples (HBO-1-A1, and some Power Cores) have been defying our collective investigative ability, but we’ll be sure to pick this up with a fresh angle next time.

Athena, Ed, Nathan, and Vizma spent all 4 hours on a single soil sample in a show of sheer determination.

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