SMRI Seminar: Klapper -- Like Squeezing Water From a Stone; Phototrophic Subaerial Biofilms Growing on Porous Substrata

SMRI Seminar 

Like Squeezing Water From a Stone; Phototrophic Subaerial Biofilms Growing on Porous
Substrata 

Isaac Klapper, Temple University 

Thursday 17th September, 1.00 - 2.00pm 

SMRI Seminar Room (A12 Macleay Room 301) 

Subaerial biofilms (SABs) are microbial communities that colonize exposed surfaces, both
built and natural.  Their function is tightly coupled to environmental conditions which
are frequently harsh, particularly with respect to water availability.  Even without
exposure to regular rainfall, it is hypothesized that overnight radiative cooling allow
SABs to utilize condensation, i.e., dew, to gather high activity water, in order to be
productive during the early morning before evaporation becomes significant.  Further, it
is proposed that SABs are able to effectively seal substratum pores to store condensed
(or precipitated) water to offset evaporation for some time.  A physical theory, based
on the Hertz-Knudsen equation for describing evaporation/condensation at liquid-gas
interfaces, is constructed.  To test the theory, the derived mathematical model of water
activity in SAB-stone systems is compared to prior laboratory data of water transport in
limestone samples with and without SAB growth.  We show that the model is able to
successfully explain differences in the data between the two cases.  Implications for
SAB growth in the environment are discussed.