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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.

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.

Related Project:

From Animal Farms to Oyster Beds: Tetracycline Resistance Genes in the Altamaha River Watershed and Estuary     
     A.L. Barkovskii, C. Coleman, A. Bozdag, G. Kohlhagen, L. Pierce, C. Green, Georgia College and State University

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This page was updated September 11, 2009