Tag Archives: decomposition

Peter’s Winter Project

Peter, an undergraduate student in my lab, is interested in winter ecology – a little studied field that is more or less assumed to be of limited relevance in temperate systems, at least in comparison to warmer seasons.  In the winter, ecosystem and community functions slow or stop all together.  For example, primary productivity halts in deciduous trees, yet likely still occurs in microorganisms, and invertebrate community interactions (i.e., predation) are simply slowed due to an overall decrease in metabolic rates.  Of the multitude of processes or interactions open to investigation, Peter decided to assess decomposition dynamics of leaf litter under the snow, and address effects of snowfall on these dynamics.  To do so, five blocks with three treatment plots each were marked and sampled by removing subsamples of leaf biomass from each of the three treatment plots within blocks.  Within each block, snow from one treatment plot was removed and added to another, so that there was a treatment plot with ambient snowfall, snowfall removed, and snowfall added.  Now, if we could only find enough freezer space…

Peter Euclide's winter decomposition - 12.22.2010 - 11.06.59-1
Peter points out a potential area to set up a block
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An added- and a removed- snow cover plot
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Chris and Peter survey the finished block

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Tools of the trade

Peter Euclide's winter decomposition - 12.22.2010 - 13.37.05-1
A sampling area - leaf material was removed from beneath the snow
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Three subsamples cleared of leaf material
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Chris surveys for the next subsample to process
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Snow is carefully excised
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All in one shot

Peter Euclide's winter decomposition - 12.22.2010 - 14.13.14-1
Sometimes, not all the snow is removed in one shot... this leads to cold hands, since only rubber gloves were used

Peter Euclide's winter decomposition - 12.22.2010 - 14.13.37-1
Peter cuts a cake of snow

More decomposition bundle collection

A few more photographs of the second collection period.  It was a cloudy, humid morning, and the colors turned out a bit differently than last time because I know nothing about white balance. Additionally, a whole subset of photo I took where more or less ruined by the humidity – condensation had formed on my lens and made the images fuzzy.  I’ve included one of those images though.

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Diversity effects on decomposition field collection

A couple of days ago, I collected a set of decomposing plant material bundles for my diversity effects on decomposition study.  Again, this sequence illustrates some of the methods used to collect the ‘decomposition bundles’ – a combination of dead macrophyte tissue from one to five species, wrapped up with a zip-tie and attached to a string.  Replicates are attached to the poles shown here and below (there are five).

Briefly, I uncovered the bundles, carefully sniped them from the string, placed them on a white tray, and bagged them in Whirl-Paks.  From there, there is lab processing, which I’ll hopefully have a similar post for soon…

Decomposition bundle collection - 07.10.2010 - 08.12.51
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Replicate posts

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The bundle is nearly indistinquishable from the rest of the plants around it.
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A tray filled with individual bundles, waiting to be bagged.

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Number 2.
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Clipping a bundle from the string.

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Recording bundle identification numbers
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A potato sack was used to carry finished samples. It nicely floats in the 1.5 m of water.

Decomposition bundle collection - 07.10.2010 - 08.59.30
Next time, I'm going to try to get a photograph of myself, to illustrate the depth.
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Bagged samples.

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Collection gear.

Diversity effects on decomposition

Here’s a big post illustrating a decomposition assay I recently set out in the wetland.  I created bundles of dead, dried macrophytes in various mixtures, attached them to 3-m of nylon rope and tied the rope to posts in the wetland.   I’ll be collecting a sample soon and may post another sequence.

Diversity effects on decomposition bundles and methods - 07.01.2010 - 15.20.04
The overall weighing set-up
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Bundles of different plant mixtures were separated and stored in these mesh bags until use.
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A pile of cattail waiting to be weighed.

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Some bundles were placed in a bucket

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Data entry
Diversity effects on decomposition bundles and methods - 07.02.2010 - 12.08.11
Accumulating bundles

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A poor photo, but this shows the raw material - large bags of dried plant.

Diversity effects on decomposition bundles and methods - 07.02.2010 - 14.25.06
A few small piles of water lily, water hyacinth and Neptunia.
Diversity effects on decomposition bundles and methods - 07.02.2010 - 14.55.13
A tag and ziptie.
Diversity effects on decomposition bundles and methods - 07.02.2010 - 14.26.04
Piles

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Finished bundles
Diversity effects on decomposition bundles and methods - 07.03.2010 - 07.58.26
An array of 21 different combinations of organic matter
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Diversity effects on decomposition bundles and methods - 07.03.2010 - 08.25.30
Each bundle was attached to a nylon rope
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Imagine 3 m of this!

Diversity effects on decomposition bundles and methods - 07.03.2010 - 14.43.00
Post placement in the wetland.
A view of the posts
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A sinking bundle

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Number 70

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Another bundle
Views from the fence - 07.03.2010 - 14.47.34
The wetland is deeper and more lush this year