Duluth professor finds corrosion-causing bacteria

Published 1:32 pm Thursday, October 30, 2008

An iron-oxidizing bacteria found in the Twin Ports could be eating away at docks and other steel structures, a University of Minnesota, Duluth, professor has found in new research.

Randall Hicks discovered the bacteria in samples collected by a diver.

The bacteria form a biofilm that can develop a positive electrical charge, Hicks said. Iron is pulled from the steel surfaces by a kind of “electroplating in reverse,” he said.

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“These types of bacteria are notoriously hard to isolate and grow,” said Hicks, adding that they seem to thrive only in particular conditions. The organisms can prosper only in a low-oxygen — but not oxygen-free — environment, he said.

A scientist at the Naval Research Laboratory in Mississippi’s Stennis Space Center has been using an electron microscope to study samples and has found bacteria that appear to match the ones Hicks isolated.

Researchers are encouraged by the work, but Hicks says he can’t yet conclude that the bacteria is the root cause of the corrosion problem.

“It may be a group of micro-organisms working together as a consortium that are responsible,” Hicks said.

The steel in the Twin Ports has been shown to corrode up to 10 times faster than experts would expect in a freshwater environment.

Diver and engineer Chad Scott of AMI Consulting Engineers said the accelerated corrosion in the Twin Ports started in the mid-1970s.

Government officials have spent more than $500,000 in the past two years to study the corrosion issue and look at solutions.

Hicks said there’s more research to be done on the corrosion issue, but he remains hopeful that officials can come up with a solution based on the cause.

“I’m hopeful that through gaining a better understanding of the problem, it will lead us to better means of remediation,” Hicks said.