Research Task 2 In situ multi-optical fiber sensor system.

Postdoctoral position. Supervisor: Dr Frank Wenzhoefer. Host: MPI

Benthic oxygen consumption is the most widely used measure of the total organic matter mineralization in  marine sediments since oxygen acts as the ultimate electron acceptor^(1,2). However, the oxygen penetration  and dynamics in marine sediments varies greatly over space and time^(3,4). This fact has lead to variety of  instruments measuring at different scales like microsensors, benthic chambers and planar optodes (e.g. 4).  The proposed multi-optical fiber sensor system will measure the oxygen distribution over large areas together with a high spatial resolution at many different locations that can be several tens of hundreds of meters or microns apart. Indeed, the sensor system is extremely flexible with respect to scales of operation,  from microns to km. The basis of the instrumentation is the single-point fiber optical oxygen sensor^(5,6,7) developed for  2-D imaging, using foils with fluorescence chemistry^{(8,4,9,10,11)} The number of sensing  points can be several thousands, thus an intelligent approach and dedicated software is needed to  de-convolute the raw signals, to calculate the signals to oxygen concentrations, and to organize the large amount of data.

For this task, a Post-Doc with experience in environmental studies, instrument construction and programming  is needed.

⁽¹⁾ Canfield D.E. et al., 1993. Mar. Geol. 113, 27–40. ⁽²⁾ Thamdrup, B. & D. E. Canfield. 2000. In Methods in ecosystem science 86–103. ⁽³⁾ Wenzhöfer F. & Glud RN. 2002. DSR I 49, 1255-1279. ⁽⁴⁾ Wenzhöfer F. & Glud RN 2004. L&O, 49 (5) 1471-1481. ⁽⁵⁾ Klimant, I., et al., 1997. Sens. & Act. B 38-39:29-37. ⁽⁶⁾ Holst, G., I. et al., 2000. 143-188. Chemical sensors in oceanography. ⁽⁷⁾ Wenzhöfer F, et al., 2000. Mar. Chem. 69, 43-54. ⁽⁸⁾ Glud, R. N., et al., 2001. L&O. 46:2073-2080. ⁽⁹⁾ Franke, U.L. et al., 2006. L&O. 51:1084-1096. ⁽¹⁰⁾ Polerecky, L., et al., 2005. L&O Methods 3:75-85. ⁽¹¹⁾ Polerecky, L., et al., 2006. ES&T 40:5763-5769.