Research

Culture-Based Analysis

Impact of Tourism on Kartchner Nonculture-Based Analysis Culture-Based Analysis Fungi Nematodes

An initial research goal is to gain a better understanding of the diversity in the microbial community structure in Kartchner Caverns.   To do this we are investigating the variability in bacterial community structure among different speleothems (inter-speleothem variability) or within the same speleothem (intra-speleothem variability).  We are using a variety of approaches to explore these samples including approaches that areculture-based and those that are nonculture-based.  Culture-based studies are dependent on isolating bacteria from the samples.  Nonculture-based studies depend on analyzing community DNA that is extracted from the samples.

As complement to our nonculture-based analyses we are building a Kartchner Caverns Culture Library. We are cultivating isolates from speleothem surfaces using several different growth media (See Figure 1 below). Following isolation, we identify each culture through sequencing of the 16S rRNA gene.

Figure 1. (below)

Cultiivating isolates from Kartchner Caverns, an example of the same sample grown on R2A, VL55 with xylan, and cave agar (made from ground up speleothem).

With the help of a humidity and CO  -controlled incubator we try to mimic the cave environment.      (Figure 2).

Figure 2. (left) Using this incubator "the mini cave" we can control the carbon dioxide in the atomosphere as well as the humidity to mimic the conditions found in Kartchner Caverns.

 

In future studies these isolates will be tested for different activities like production of secondary metabolites such as biosurfactants or antibiotics.  We are also testing them for the ability to deposit calcium carbonate crystals ( Figure 3).  The production of calcium carbonate crystals could be an indication/hint for the answer of one major unresolved question in connection with microorganisms living in the cave. Are these microorganisms involved in the growth of the speleothem carbonate formations?

The objective of the culture- and nonculture-based studies is to get a better understanding for the microbial diversity in Kartchner Caverns. In the next step we will utilize a metagenomic approach to identify both the types of microorganisms present and gain insights into the environment specific to Kartchner speleothems.

Figure 3. (right) Calcium carbonate crystals deposited by a Kartchner Caverns isolate.

 

updated 7/2009