INTRODUCTORY NOTES
For the data table in this data package, the air dry weight, in grams,
of the dust sample in each collector is calculated from the mass of
the sample and the bag minus the average mass of all bags used during
the collection ( (Bag + Sample) - Avg_Bag_Wt ). Data collection flags
and observations impacting the quality of these sample weights are
indicated in the “qwt” and “comments” columns of the data table.
Methodology document: Conn_BSNE_Collection_Procedure.doc
Plot maps: Locations of BSNE stands within the plots are found in
ConnectivityMicroplotMaps_A-D-G.pdf.
Historical log: Connectivity.his
COMPLETE CONNECTIVITY BSNE COLLECTION PROCEDURE
Basic Set Up and Location:
There are 3 sites for this study: Gravelly Ridges, Aeolian, and Dona
Ana. Within each site, there are 8 plots. The plots are 8x8 meters
and have an 8x8 buffer zone on both sides of the plot (up and down).
There are four BSNE stands for each plot, 2 in each of the 2 buffer
zones (8 collectors per plot). Each stand contains 2 collectors, 10cm
and 30cm. These BSNEs are in a fixed position and all collectors
should be pointing the same direction. The collectors in the upwind
buffer are facing away from the plot and the collectors in the
downwind buffer are facing into the plot. The idea is the upwind
BSNEs measure the amount of dust entering the plot, and the downwind
BSNEs measure the amount of dust moving off the plot. This provides a
measure of the effectiveness of the plot obstructions to wind blown
dust. It is important the BSNEs are fixed in an orientation that
points across the full length of the plot. Maps of the location of
each stand within the plots are found in
ConnectivityMicroplotMaps_A-D-G.pdf.
Collection Guidelines:
1. The Connectivity BSNEs are collected quarterly in February,
May, August, and November. They should be collected in the last week
of the month and if not able, then the first week of the next month.
2. Use 6x4 inch, 4-mil Ziploc-style bags to collect samples.
(When ordering bags, make sure you order 6x4 NOT 4x6 since the width
is 6 inches and the length is 4 inches. Vender: National Bag Company,
Inc., 800-247-6000, Part #90-760C6, 1000 bags/box)
3. The bags need to be preweighed before going to field. It is
best to do this is as small of numbers as possible to get a better
average. 10 at a time is appropriate.
4. Individual collection bags should be labeled as follows: Site
(A, D, or G), Plot # (1-8), Stand # (1-4), and Height (10 or 30). So
Aeolian site, Plot 3, Stand 1, 10 cm collector would be labeled:
A3-1-10.
5. All bags from one site should be placed in a larger bag that
is labeled with the site name, date collected, and the average bag
weight.
NOTE: If you need to use multiple large bags to hold a particular
site, make sure that all of the appropriate identifying information is
on each of them. Write a set number on bags when multiple large bags
are used; e.g., "1 of 2" if there are 2 large bags for All
NPP. This will reduce chance of samples being misplaced.
Collection Procedure:
1. To collect a sample, slide the cover off of the collector and
put the narrow end of the collector inside the bag. Use a stencil
brush to brush out all dust possible, paying close attention to dust
caught on screws, behind the opening, and in corners. Remove most of
the air and seal the bag shut. Shake out any debris above the screen,
inspect the condition of the collector, slide the cover back on, and
place the collector back on its fin.
2. Record collection dates and times and any sample or
maintenance notes in the LTER V Connectivity Pilot Study LTER study
#308, BSNE Sample Collection Book at time of collection. This is kept
in the filing cabinet in office 211.
3. A "pinch" or about 0.10 g is minimum sample size to
collect. If a collector has less than this, dump the sample out and
do not collect it. Make a note on the datasheet that it was not
collected and why. Collect all others that have the minimum sample
size.
4. Do not collect samples out in the open if it is windy enough
to blow some of the fine dust away, as this will bias the samples in
the particle size analysis.
5. If a collector has water in it, do not collect the sample.
* Wait until the collector dries out naturally and collect
it then.
* If one or more collectors are wet and others are dry, do
not collect the dry collectors until the wet ones dry out.
* All collectors that will be compared with each other
should be collected on the same day. (All collectors within a sampler
and all samplers within a site should be collected at the same time.
* If many samplers at a site have wet collectors, postpone
collection until they are all dry.
* If some have been collected before you realize that
others are wet, use your best judgment as to whether the remainder of
the site should be collected or postponed. (I.e., What will allow for
the best comparison? If the majority were collected before the wet
ones were discovered, finish the site, and collect the others as soon
as possible.) Do NOT throw out samples that were already collected!
6. If samples are not collected on the expected date(s), a
history log entry should be made explaining the delay so that Greg
knows that he is not missing samples from the expected dates. The
appropriate history log file can be found at connectivity.his.
7. If a collector is completely full with dust (i.e. potentially
overflowing), it should be dumped in the field and not collected. A
note should be made in the appropriate databook.
8. If there are spider webs inside or in the opening of the
collector, remove the spider web and do not put it in the sample bag.
Make a note in the data book and record whether part of the sample
might have been lost (due to sticking to the web) and approximately
how much. (For estimating amounts, don't use "a little" or
"a lot." These are very subjective terms. A
"pinch" or "half a teaspoon" or "~0.5
gram" are better qualitative answers.
9. If there is debris in the sample and the debris is easy to
remove without removing sample along with it, do not include the
debris in the sample. We are only interested in sand and soil, so
leaves, insects, and twigs can be removed. However, if dust is stuck
to the debris or the debris is too small to grab without grabbing dust
too, collect the debris along with the sample.
10. If there is rust or paint flakes in the sample, collect the
sample and make a note in the appropriate data book of the
contamination and amount of contamination. These collectors should be
replaced.
11. If there is white mineral crust on the inside of the
collector, make a note of this, too. These collectors should be
replaced and cleaned in the lab. Note: a white, airborne dust
deposition has occurred in the past that is part of the dust sample
and should be collected. A mineral crust is a metallic reaction and
would need cleaning with LimeAway in the lab to remove it. This has
not occurred for many years and the manufacturing process may have
improved that alleviates the potential. Document its occurrence and
notify John Anderson if this occurs.
12. When a collector is replaced, record in the databook when it
was replaced and the reasoning of doing so.
13. It is very important not to stand or kneel in front of the
BSNE collector opening. Stay behind or to the side of the collectors
at all times to minimize soil disturbance in the prevailing wind
direction. When it is necessary to walk near the samplers (i.e.,
during maintenance or collection) minimize disturbance by walking
flatfooted and smoothing out any disturbances made.
Maintenance:
1. Clip to ground level any vegetation growing immediately in
front of the fixed collectors to allow unrestricted dust entrance.
Avoid disturbing the ground in front of the collector.
2. The height of the collectors needs to be checked periodically,
especially during windy periods or following overland water flow when
scouring can remove soil from the ground surface below them. The
height should be measured to the bottom of the opening of each
collector to the ground.
3. To lower the height of the sampler as a whole, hammer down the
sampler stem (center pipe on which the dust collectors are mounted).
A tape measure should be kept in the "Icky Box" at all
times. The angle of the sampler stem must also be checked, especially
after height adjustments are made. The sampler stem should be
vertical, parallel to the plane of gravity.
4. If the distance between the collectors has changed (as opposed
to the whole sampler moving as a unit) or if sampler height must be
increased, loosen the screw on the collars that the fins rest on.
Move the fins to the appropriate height, and re-tighten the screws.
5. Any collector with excessive mineral crusts developing inside
(caused by rainwater evaporation) should be brought back to the lab to
be cleaned. A few drops of Lime-Away will dissolve the crust so it
can be wiped out easily. The collector should be rinsed thoroughly
when done; the samples may eventually be analyzed for mineral content
and we don't want Lime-Away to be the primary constituent. Please
note any excessive deposition in the data book at the time of
collection and record that it was removed and why it was removed.
6. If a collector is rusted or has holes in it, it must be
replaced.
Sample and Data Processing:
1. The samples are brought back to the lab and individually
weighed (plastic bag + sample).
a. Record data on Connectivity BSNE lab datasheets. Print
these forms from Connectivity_BSNE_sample_weights_lab_datasheet.xls.
b. Weigh and record sample weight to 3 decimal places.
c. When weighing, make sure that no part of the sample bag
is touching anything but the weigh pan it rests on. Do not let the bag
touch the edge of the scale cover or body of scale; this will affect
the weight.
d. It helps to tare a medium sized bolt to hold down the
sample bag when it is folded in half on the scale. This keeps the bag
from moving around and results in a more accurate weight. The weight
will also stabilize more quickly if the bag is not changing shape
during the weigh process.
2. Data entry
a. After weighing all samples, the weights need to be
entered and error checked (verified) into
Connectivity_BSNE_sample_weights.xls.
b. The field data from the databook also needs to be entered
into this same spreadsheet.
3. After all data has been entered and error checked:
a. Dust samples will be retained and archived here at the
Jornada (as of 11/16/2010).
i. Data file: Connectivity_BSNE_sample_weights.xls
ii. History file: Connectivity.his
4. When samples are moved to the archive storage location , make
sure to log the samples into the Shipping Log, including date and
sample sites. This documentation of when and where the samples went is
important for tracking purposes.
