Dr.
Roy Cullimore
Lori Johnston
Droycon Bioconcepts, Inc.
Regina, Saskatchewan, Canada
Provided by NOAA Ocean Explorer
Tiny microbes are at work 3,800 m under the sea at the
site of the Titanic shipwreck. The microbes feed off
iron from the ship, forming icicle-shaped “rusticles.”
Although rusticle formations on Titanic have been observed
for many years, not much effort has gone into studying
them. This expedition sent two Mir submersibles to survey
the microbes that are infesting the ship and to determine
their rate of growth. In 1998, four steel test platforms
were placed in various locations near and on the wreck
to assess the growth of rusticles on steel in different
stages of fatigue. This expedition visited these platforms,
and the video imagery revealed that all four showed
strong evidence of rusticle growth. The longest rusticle
extended 2.5 inches from the steel coupon.
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A rusticle hanging from the stern section of the
RMS Titanic shows secondary growths during maturation.
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One of the experiments conducted on this expedition
was to see if a common species of surface-dwelling bacteria
could survive exposure to the conditions at the Titanic
site. In 1998, five species were sent to the site and
survived for 18 hrs with losses of no more than one
order of magnitude of cells. This year, the experiment
was limited to one species of bacteria (Pseudomonas
aeruginosa) with replication made possible using the
BART reader system. This data showed that survivors
from the dive (without any protection from the conditions
at the site) were impacted to a varying degree, from
no reduction of cell activity to less than one order
of magnitude of reduction. One of the replicates showed
three orders of magnitude reduction in cell activity.
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Detached rusticles below the portside anchor indicate
that these icicle-like formations pass through
a cycle of growth and maturation, then fall away.
This particular “crop” was probably
in a 5- to 10-yr cycle.
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Rusticles growing down from Titanic's stern section.
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Further observations were made on the deterioration
of the bow and stern sections of Titanic. From these
observations it appears that the stern section of the
ship is deteriorating at a faster rate than the bow
section, and has been calculated to be about 40 yrs
ahead of the forward section. This was determined due
to the state of the steel at the stern, which was severely
embrittled and distorted, providing better "habitat"
for rusticle formation. Also, because food was stored
on Titanic primarily in the stern section of the ship,
it supplied the initial nutrients for rusticle growth.
Lastly, surfaces within the hull that had been torn
apart served as a staging ground for rusticle growth.
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