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Dear Marilyn, Dave and others,

I don't think food webs have to be redrawn, the C and N spacing between
host blood and whole ticks was quite ordinary in this short study:

Natural isotope signatures of host blood are replicated in moulted ticks.
Ticks and Tick-borne Diseases, Volume 2, Issue 4, December 2011, Pages
225–227.
http://dx.doi.org/10.1016/j.ttbdis.2011.09.006

Best wishes,
Olaf

On 21 January 2016 at 21:53, Marilyn Fogel <[log in to unmask]> wrote:
>
> Dear Isotope Geochemists,
>
> In trolling through back emails, that I needed to attend to, the subject
line “petroleum jelly” turned up. What in the heck are isotope geochemists
doing with petroleum jelly? Well, my mind raced to ridiculous places—places
where the minds of isotope geochemists probably should not go! Especially
when they are supposed to be working.
>
> However, upon closer inspection, the message was even more
“interesting”—petroleum jelly on ticks! Ugh. Years ago, my former
Geophysical Lab Director Hatten S. Yoder, Jr., brought a bunch of ants into
the lab for me to analyze. He was the Director, you understand, well the
former director, but a nice man, so I took the time to analyze them
carefully. One of my colleagues remarked scornfully, “You’ll never get into
the Academy if you spend your time analyzing ants.” Turned out he was
right. I might draw the line at ticks, though when I think about it--ticks
feed on blood. We just analyzed some polar bear blood in the lab yesterday.
(Do polar bears have ticks?)I can see food web and trophic discrimination
concepts being challenged by the tick hypothesis, perhaps resulting in new
paradigms.
>
> Seriously, I would attempt to wipe the petroleum jelly off of the ticks,
as much as possible, using a kimwipe. According to Wikipedia, petroleum
jelly is made of >25 C-hydrocarbons. Then I would rinse/soak the
tick+petroleum jelly in dichloromethane: methanol (9:1) for about 15
minutes. Look at the tick, the solution, and determine if you are damaging
the tissue. Repeat if the solvent looks clear. You don’t want to over
extract the tick, then you’d lose it’s lipids. As for picking off chitin,
Arndt Schimmelmann and others have shown that the d15N of chitin is very
different from bulk tissue, because of isotope fractionation in making
N-acetyl glucosamine. Stick with the whole tick tissue. (Yuck) Also,
analyze a bit of the petroleum jelly itself. It might have a very different
d13C value that could be used to determine if it is still contaminating
your samples. Last, with uncontaminated ticks, measure the C/N. Use that
value in determining whether your petroleum jellied ticks might still have
some petroleum jelly on them.
>
> Do we need a tick isotope standard, like we have for leaves and collagen?
I’ll stop now.
>
> Marilyn Fogel
>
>
>
> From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of
William Patterson <[log in to unmask]>
> Reply-To: Stable Isotope Geochemistry <[log in to unmask]>
> Date: Wednesday, January 20, 2016 at 11:54 AM
> To: "[log in to unmask]" <[log in to unmask]>
> Subject: Re: petroleum jelly
>
> Hi Dave,
> Are you analyzing the whole ticks or portions of the exoskeletal chitin?
> Cheers,
> Bill
>
> On Wed, Jan 20, 2016 at 1:18 PM, David Gillikin <[log in to unmask]>
wrote:
>>
>> Hi all,
>>
>> Someone who would like to analyze ticks for d13C and d15N in my lab, but
some of the ticks have been exposed to water mixed with petroleum jelly
(this is how they deal with escapees). Is there any way to safely wash them
without further contamination?
>>
>> Thanks,
>> Dave
>> _____________________________________________________________________
>> David P. Gillikin, Ph.D.
>> Associate Professor of Geology
>> Director: Union Stable Isotope Laboratory
>> Union College
>> Department of Geology
>> 807 Union St.
>> Schenectady, NY 12308
>>
>> Office phone: (518) 388-6679
>> Lab phone:     (518) 388-8741
>> email:  [log in to unmask]
>> web: http://minerva.union.edu/gillikid/
>> Lab Website: http://minerva.union.edu/gillikid/lab.htm
>> ______________________________________________________________________
>>
>
>
>
> --
> Dr. William P. Patterson
> Professor and Director, Saskatchewan Isotope Laboratory
> 114 Science Place
> Saskatoon SK S7N5E2
> Canada
> http://geochemistry.usask.ca/bill.html
> https://usask.academia.edu/WilliamPatterson
> https://www.researchgate.net/profile/William_Patterson/