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Zhu, Q. ., Stony Brook University, Stony Brook, USA, qzhu@notes.cc.sunysb.edu
Aller, R. C., Stony Brook University, Stony Brook, USA, raller@notes.cc.sunysb.edu

TWO-DIMENSIONAL FERROUS IRON DISTRIBUTIONS IN MARINE SEDIMENTS REVEALED BY A NOVEL PLANAR OPTICAL SENSOR

A planar optical sensor was developed for measuring two-dimensional ferrous distributions in marine sediments with high resolution. Ferrozine is used as indicator and the sensor absorbance shows good linear relationships with ferrous iron concentration in the range of 0 – 200 µM, with a detection limit of 4.5 µM. The sensor response time is 30 min at room temperature, and response is independent to temperature, dissolved oxygen, salinity and pH change under anoxic conditions. No interferences from other major components and trace metals in seawater were observed. The sensor is simple, stable and precise, and has been successfully used to measure two-dimensional ferrous distributions in intertidal flat and subtidal sediment samples. The sensor reveals the complex heterogeneous distribution patterns of ferrous that are often associated with both inhabited and abandoned biogenic structures in surface sediment. When images are spatially averaged, 1-D vertical profiles typically measured by pore water separation techniques are readily obtained. Traditional sampling obscures the true range of ferrous iron actually present, whereas the sensor provides a basis for accurate resolution of kinetic, equilibrium, and transport relationships

Poster presentation

Session #:148
Date: 2/22/2012
Time: 17:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: A0339