GCRC Project Summary |
Geochemical and Microbial Signatures for Anthropogenic Disturbance of Coastal Environments
PIs: Andrei L. Barkovskii (Georgia College and State Univ.), Dave S. Bachoon (Georgia College and State Univ.), and Johannes E. Leisen (Georgia Inst. of Tech.)
Support:
Sea Grant College Program
Timeframe: 2003
- 2004
Project Objectives:
1. To evaluate whether the molecular profiles of sediments obtained with 13C MAS NMR are reflective of the degree and the nature of anthropogenic disturbance of coastal environments and can be used as geochemical indicators.
2. To evaluate whether the relative distribution and abundance of tetracycline
resistance genes in the sediments are reflective of the degree and the nature
of anthropogenic disturbance of coastal environments and can be used as microbial
indicators.
Findings:
We have analyzed the abundance and distribution of Tet-resistant microorganisms
in two Georgia coastal areas, the Altamaha and Savannah River estuaries. The
relative and absolute contents of Tet-resistant microorganisms among both freely-dispersed
and particle-associated microbial fractions in the Altamaha River sediment were
found substantially higher than corresponding contents in the Savannah River
sediment. Moreover, the Altamaha River microorganisms demonstrated substantially
higher levels of resistance to tetracycline, up to 50 ppb vs. 1 ppb for the
Savannah River isolates. The highest abundance and highest levels of Tet-resistance
were observed among strongly particle-bound microbial communities. The latter
observation suggests that Tet-resistant microorganisms and/or corresponding
genes have become associated with indigenous microflora of estuarine sediments.
Obtained results support our hypothesis that the abundance of Tet-resistant
microorganisms in an estuary is proportional to the degree of its biological
contamination due to agricultural run-offs. Their primary accumulation within
sediment particles indicates a severe deterioration of the Altamaha river estuary
and its biological contamination.
Planned Publications:
Barkovskii,
A. L., H. Fukui, S-H. Kim, T. L. Marsh, A. I. Khijniak, J. Leisen. 2004 Spatial
and Taxonomical Organization of Microbial Communities during Microbial SOM Diagenesis.
Barkovskii, A.L.,
Kohlhagen, G, Atkas, Y. 2004 Abundance and Distribution of Tet-resistant Microorganisms
in Estuarine Sediments.