The effect of Manganese on the native algal species Pseudokirchneriella subcapitata Emily Christine

1
The effect of Manganese on the native algal
species Pseudokirchneriella subcapitataEmily
Christine SidersMarietta College

• Methods
• Three 50 ml flasks were used for each of the
  four concentrations. Each flask contained
• 9 ml of ultra pure water
• 2 ml of Pseudokirchneriella subcapitata
• 9 ml of Alga-grow Medium
• For the control condition, no MnCl2.4H20 was
  present in the Alga-grow Medium, while 5, 50, or
  500 ppm was present in each experimental
  condition. The Twelve flasks were stirred
  continuously on a shaker under a 12 hour
  light/dark cycle. Each concentration of the
  Pseudokirchneriella subcapitata cells were
  counted daily for five days with a hemocytometer
  then calculated for total number of cells in each
  flask. The formula is as follows
• cells per milliliter n/10 x 250,000
• where n total number of counted cells
• A total of three replications were
  conducted and the data were analyzed using SPSS.

• Introduction
• Manganese is one of the main pollutants in
  the Marietta, Ohio area due to Eramet. Eramet is
  the leading producer of ferromanganese alloys in
  the world as well as producing manganese based
  products for the chemical industry. According to
  a 2005 investigation by the US Department of
  Health and Human Services, the Ohio River in
  Washington County, Ohio has a manganese
  concentration of approximately 5 parts per
  million. The elevated concentrations released
  into the environment may have an effect on
  organisms that inhabit the area.
• Pseudokirchneriella subcapitata is a
  distinct crescent shaped green micro alga that is
  found in many freshwater aquatic ecosystems,
  including the Ohio River. Its short life cycle as
  well as the little space and care that is
  required for it to flourish makes
  Pseudokirchneriella subcapitata an ideal organism
  for laboratory use in toxicology studies as a
  bioindicator. Bioindicators are used to monitor
  the health of an environment or ecosystem.
• The purpose of this experiment was to look
  at the effect of manganese on the growth of an
  algal species native to the Ohio River in
  Washington County, Ohio. Further, to develop an
  understanding of toxicology as well as build on
  basic lab techniques.
• It was hypothesized that the lowest
  concentration of manganese (5 parts per million)
  will not have a significant effect on the
  population growth of Pseudokirchneriella
  subcapitata, while the higher concentrations of
  50 and 500 parts per million will have a
  detrimental effect on the population growth.

• Results
• The overall growth rates (in cells/ml/day)
  for each condition are shown in Table I. Figure
  I illustrates the cumulative daily averages for
  each condition throughout the trials.
• A 4 (conditions) x 5 (day) Mixed Factor
  ANOVA was used to analyze the data. There was a
  significant main effect of condition F (3,32)
  26.71, p lt .001 as well as a significant
  interaction of condition and day, F (12,128)
  16.77, p lt .001. All conditions were
  significantly different except for the 50 ppm and
  500 ppm (p .312).
• Discussion
• The lowest concentration of manganese (5
  ppm) did not have a significant effect on the
  population growth of Pseudokirchneriella
  subcapitata, while the higher concentrations of
  50 and 500 ppm did have a detrimental effect on
  the population growth. This research suggests
  that increasing levels of manganese may cause a
  decline in native alga species, which has
  significant implications for the Washington
  County, Ohio area. In future research, more
  replications as well as concentrations under 50
  ppm should be used due to the significant decline
  of growth seen at the 50 ppm condition.
• References available upon request.

Table I Overall growth rates (cells/ml/day)
Figure I Cumulative average cell counts for
trials I, II, and III
Acknowledgements Dr. Brown, Dr. Hogan, Mrs.
Jarrell, Biology senior capstone class, Dr.
McCabe, Dr. Pate, Dr. McKay, Dr. Tschunko,
Marietta College Biology Department, Andrea
Marion, Allison Rhea, Christiana Hilditch, and
David Borrelli.