UNIVERSITY OF IOANNINA GREECE
BIOLOGICAL APLICATIONS AND TECHNOLOGY
BIOLOGICAL APLICATIONS AND TECHNOLOGY
AQUATIC MICROORGANISMS
Team 7: Serasidis Konstantinos, Tsinoglou Makrina
Week: 4
Week: 4
Fourth week’s observation: 18/11/2016
Between the
previous weeks and this week’s observations several changes have been noticed
in the Control column. Firstly, at the bottom of the column green color has
been noticed. Specifically, these changes state the growth of green sulfur
bacteria. These bacteria require anaerobic conditions, sulfide ions and light
effect in order to photosynthesize. Also, at the bottom of the column are
noticeable black spots that are caused by anaerobic sulfur-reducing bacteria. These
bacteria use either sulfate or oxidized forms of sulfur as the terminal
electron acceptor, generating large amounts of H2S. The H2S
will react with any iron in the sediment, producing black ferrous sulfide. At a
higher level of the column a brown color in the sediment shows the growth of
heterotrophic bacteria. There is a green color band immediately above the
sediment. The green colored band is caused by the diffusion of H2S
from the sediment into the water column that enables anaerobic photosynthetic
bacteria to grow. The orange color in the water of the column that is caused of
purple non-sulfur bacteria seems to be the same as the previous week. Finally,
biofilm is observed at the top of the water column. A biofilm is any group of
microorganisms in which cells stick to each other and often these cells adhere
to a surface.
At the
bottom of the column in the dark, the sediment is observed darker in comparison
with the previous week. The darker color of the sediment indicates the increasing
growth of anaerobic bacteria. Also, black spots are noticed at the lower levels
of the sediment that are caused by anaerobic sulfur-reducing bacteria. Additionally,
the black band which formed at the upper levels of the sediment is caused by
the growth anaerobic sulfur-reducing bacteria. The anaerobic conditions are formed
by the diffusion of H2S from the sediment into the water column. Finally, biofilm is observed at the top of the water column.
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| 2.Column in the dark |
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| 1. Control column |
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