SS4.02 The Role of Microbiology in Trace Metal and Organic Contaminant Cycling in Aquatic Systems
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
PortaD, Bowling Green State University, Bowling Green, USA, dporta@bgnet.bgsu.edu
Bullerjahn, G, S, Bowling Green State University, Bowling Green, USA, bullerj@bgnet.bgsu.edu
Durham, K, A, Bowling Green State University, Bowling Green, USA, kathyr@bgnet.bsgu.edu
Wilhelm, S, w, University of Tennessee, Knoxville, USA, wilhelm@utk.edu
Twiss, R, M, Ryerson Polytechnic University, Toronto, Canada, m2twiss@acs.ryerson.ca
Sterner, R, W, University of Minnesota, Saint Paul, USA, stern007@tc.umn.edu
McKay, R, M, Bowling Green State University, Bowling Green, USA, rmmckay@bgnet.bgsu.edu
 
PHYSIOLOGICAL CHARACTERIZATION OF A SYNECHOCOCCUS SP. STRAIN PCC 7942 IRON-DEPENDENT BIOREPORTER GROWN IN DEFINED TRACE METAL MEDIA
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The complex nature of Fe speciation in natural waters makes it difficult to assess Fe availability to phytoplankton when considering only data derived from standard chemical analysis. As a complementary approach, we have developed a cyanobacterial Fe responsive bioreporter constructed in Synechococcus sp. PCC 7942 using the Fe-responsive isiAB promoter and the Vibrio harveyi luxAB reporter genes. A comprehensive physiological characterization of the bioreporter has been made in trace metal-defined Fraquil medium at pFe 21.6, pFe 20.6, and pFe 19.5. With this, we have demonstrated that the bioreporter elicits a variable luminescent signal in response to Fe deficiency. In addition, calibration of bioreporter luminescence has been made over this range of pFe values and demonstrates a linear response over much of this range. Its applicability to assess Fe availability in the natural environment has been tested using water samples from Lake Superior and Lake Erie. Parallel assessment of dissolved Fe and bioreporter response from these samples reinforces the idea that measures of dissolved Fe are not always a valid indicator of Fe availability.