Mold on mollusk shells

Jill K. Harris <jillharr [at] vmnh__net> writes

>A co-worker posed the following question; and, I have no idea how to
>answer her.  Does anyone have experience with this problem?  Or,
>know anyone I could contact to discuss this with?
>
>   "I am supposed to help the people at the marine lab in Brazil
>    curate the Marcus bryozoan collection--it was stored for years
>    in humid conditions in Sao Pauli, and when I looked the
>    collection last year, I saw that many of the specimens, which
>    are on dead shell substrata, were covered with networks of
>    fungal growth--I wondered if you have any ... contacts that
>    might be able to offer advice on how to get rid of it--and keep
>    it from re-occurring. Judy"

Although I can't advise on methods of removing the fungal growth, I
can suggest a means of stopping its growth and preventing its
reoccurrence: provide a microclimate that maintains a stable
humidity level of under 60%.

This can be done by a variety of means:

    1.  You can create a microclimate in the storage room by using
        standard HVAC (air conditioning) techniques. This is the
        most expensive method, as the walls and openings to the room
        should be sealed and insulated properly, the initial
        engineering work, machinery, and fees for installation may
        be costly, and the cost of energy to maintain an adequate
        humidity level may be very dear in some areas.

    2.  You can pack the materials in sealed containers (barrier
        film bags or well sealed plastic boxes) with passive
        humidity controls (silica gel, zeolites). This method may be
        the least expensive if the collection is small, but care
        must be taken to carefully reseal all containers, and
        regular maintenance and testing must be done to ensure that
        humidity levels are properly controlled.

    3.  An active humidity controller (eg. a microclimate generator)
        can be used to provide humidity control in sealed
        enclosures. They are precision machines, so there will be an
        initial capital expense, however, in larger applications the
        cost of a microclimate generator will be less than the cost
        of silica gel for the same volume! Power draws, maintenance,
        and operating expenses are low, and beyond a reasonably well
        sealed display or storage enclosure, no special sealing or
        treatments are needed. Existing storage cabinets can often
        be used.

All the above methods will take some preparation, capital expense,
and maintenance, but all can reliably provide a microclimate that
will prevent the mold spores from developing further. Keepsafe
Systems can provide transparent barrier film bags and clips suitable
for such storage, and Microclimate Technologies International can
provide suitable microclimate generators and other precision climate
control devices. Information on both at <URL:http://www.keepsafe.ca>
or by contacting me off list.

Jerry Shiner
Keepsafe Systems
Supplies and Solutions for oxygen-free and microclimate storage
800-683-4696  416-703-4696


                                  ***
                  Conservation DistList Instance 17:50
                 Distributed: Tuesday, January 20, 2004
                       Message Id: cdl-17-50-007
                                  ***