Hello,
I've had an inquiry from a doctoral student who wishes to determine the
hardness, relative or otherwise, of the integument of zooplankton that form
the natural prey of crayfish phyllosoma. She originally proposed using a
penetrometer but the ones available to her were far too large and it's my
feeling that they all will be given the scale of her test subjects which
range from a few millimetres to a couple of centimetres. We've considered a
surface hardness instrument such as used for testing metal surface coatings
but she was concerned that the storage of samples until returning from her
sample collection cruise would affect the properties of the integument, and
the instruments available to her cannot be taken on board the ship for
testing while fresh. Another suggestion was to treat sorted samples in bulk
and dissolve the calcium carbonate fraction away with EDTA to ascertain the
% compostion ratio by weight which may be useful for the crustaceans but
perhaps not for other species. Prey species include copepods, salps, and
fish larvae. I'd appreciate any ideas anyone might have on this topic that
we could explore prior to her departure on the sample collection cruise in
mid-march. I look forward to responses with interest.
Best Regards
Peter Keen
University of Auckland,
School of Geography and Environmental Sciences
Phone: 09 3737 599 ext 88536
e-mail: [log in to unmask]
http://www.auckland.ac.nz
Best Regards
Peter Keen
University of Auckland,
SGES
Phone: 09 3737 599 ext 8536
e-mail: [log in to unmask]
http://www.auckland.ac.nz
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