Presentation Title

Mineral Precipitation Potential of Cave Bacteria and their Contribution to the Formation of Cave Speleothems

Format of Presentation

Poster to be presented the Friday of the conference

Abstract

Typically, caves are characterized by low organic carbon nutrients due to the absence of light and a high degree of oxidation due to water erosion and subsequent exposure to air (Northup & Lavoie, 2001; Ortiz et al., 2013; Barton et al., 2004). Due to the low levels of organic carbon, bacterial diversity is determined by the ability of each organism to specifically utilise the environmental conditions in that particular ecosystem. Limestone caves represent one such oligotrophic environment, including a high degree of oxygen, mild temperatures, high humidity, circumneutral pH and little-to-no exposure to sunlight (Ortiz et al., 2013). Speleothem (a secondary cave structure) composition was determined using inductively coupled plasma mass-spectrometry (ICP-MS) and provided a basis from which to develop precipitation media. To understand the role bacteria play in the formation of speleothems, we focused on microbiologically-induced carbonate precipitation, which is a form of biologically-induced mineralization (BIM), in the lab setting, whereby bacteria precipitate carbonate which coordinates with free calcium ions in the environment, thus producing calcium carbonate. In this study, bacterial isolates collected from ICC speleothems were tested for the presence of an integral MICP enzyme, urease. Urease positive (U+) isolates were grown on modified precipitation agar to provide ample time for crystal formation. U+ isolates produced crystals of varying structures and were imaged using a petrographic microscope. The next step is to grow U+ isolates in broth culture to understand the bacterial mechanisms of speleogenesis.

Department

Biological Sciences

Faculty Advisor

Naowarat Cheeptham

This document is currently not available here.

Share

COinS
 

Mineral Precipitation Potential of Cave Bacteria and their Contribution to the Formation of Cave Speleothems

Typically, caves are characterized by low organic carbon nutrients due to the absence of light and a high degree of oxidation due to water erosion and subsequent exposure to air (Northup & Lavoie, 2001; Ortiz et al., 2013; Barton et al., 2004). Due to the low levels of organic carbon, bacterial diversity is determined by the ability of each organism to specifically utilise the environmental conditions in that particular ecosystem. Limestone caves represent one such oligotrophic environment, including a high degree of oxygen, mild temperatures, high humidity, circumneutral pH and little-to-no exposure to sunlight (Ortiz et al., 2013). Speleothem (a secondary cave structure) composition was determined using inductively coupled plasma mass-spectrometry (ICP-MS) and provided a basis from which to develop precipitation media. To understand the role bacteria play in the formation of speleothems, we focused on microbiologically-induced carbonate precipitation, which is a form of biologically-induced mineralization (BIM), in the lab setting, whereby bacteria precipitate carbonate which coordinates with free calcium ions in the environment, thus producing calcium carbonate. In this study, bacterial isolates collected from ICC speleothems were tested for the presence of an integral MICP enzyme, urease. Urease positive (U+) isolates were grown on modified precipitation agar to provide ample time for crystal formation. U+ isolates produced crystals of varying structures and were imaged using a petrographic microscope. The next step is to grow U+ isolates in broth culture to understand the bacterial mechanisms of speleogenesis.