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Past Research Projects
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Geomicrobiology
of mine tailings
This
study looked at the presence and role of sulfate-reducing
bacteria (SRB) and dissimilatory iron-reducing bacteria
(FeRB) in metal cycling in Cu-Zn mine tailings. A previous
study on various mining sites (Cu-Zn and Au) indicated that
SRB could be recovered from all the tailings,but were most
abundant and active under strong redox gradients. FeRB have
been recovered from slightly acidic Cu-Zn tailings and are
suspected to compete with SRB for electron donors, such
as acetate, (NSERC).
Hg methylation
in Cu-Zn and Au mine tailings: The project looked at the
specific role of sulfate-reducing bacteria in Hg methylation
and at the physico-chemical factors affecting methylation
(COMERN).
Microbial As
reduction in sediments impacted by Au mining. This project
in collaboration with Queens University focused on the
role of As reducing and sulfate reducing bacteria in As
and S cycling in submerged tailings in the Yellowknife
Bay, (DIAND).
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Surface
reactivity of aquatic viruses
This project
looks at an important component of the colloidal fraction
in aquatic environments: viruses. They
are as abundant as bacteria in various environments and
they have the potential to sorb various metals on their
surfaces. The study looks at the acid-base reactivity of
the capside and at its ability to bind trace metals, (NSERC).
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Fe-phosphate
minerals
This
project looks at the stability of Fe-phosphate minerals
forming as a result of Natural-Phosphate-Rock (NPR) addition
to mine tailings. NPR addition is seen as an alternative
technique to attenuate acid-mine drainage because it immobilizes
Fe(III), a power oxidant of pyrite. The project will investigate
the stability of various Fe(III)- and Fe(II)-phosphate minerals
in the presence of bacteria (such as Fe- and S-oxidizers),
(CRESTech). |
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Mineral-bacteria
interactions
This
project will focus on the interactions between E. coli
and minerals as a function of nutrient addition. We suspect
that the addition of nutrients will modify the surface reactivity
of the bacterial cell wall and that it will affect its adhesion
to mineral particles, (OMAFRA). |
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Trace
metal sorption onto biogenic Fe-oxides
This
study looks at the role of bacterial surfaces in the formation
of iron oxides under freshwater conditions. Fe-oxides are
formed by the oxidation of Fe(II) at neutral pH and in the
presence of dissolved species such as sulfate, silica and
phosphate and in the presence of well characterized bacterial
surfaces. Results indicate that the mineralogy of the Fe-oxides
is not affected by the presence of bacterial surfaces during
their formation. However. the crystallinity of biogenic
Fe-oxides is affected, i.e., crystals are usually small
and poorly ordered. This is likely to impact the adsorption
of trace metals, (NSERC & U of Ottawa). |
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Biomineralization
near deep-sea vents
This
study is part of the New Millennium Project (NeMO)
which investigates deep-sea vents in the North Pacific Ocean.
Preliminary results show that in situ bacteria (Arthrobacter)
collected on basalt rocks near the vents can weather silicate
minerals and serve as a nucleation surface for freshly formed
Fe-oxides.
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