Seasonal Fluctuations of Diatom Populations in Lake Herman, SD

1
Introduction
http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
2
Classification

• Kingdom Protista
• Phylum Chrysophyta
• Class Diatomatae
• 12,000 Species of Diatoms
• With improving technology, more species are being
  distinguished is improving, more species are
  being discovered along with more detailed
  characteristics.
• As a result, classification systems are not
  always permanent.

3
Pennales

• Elongated, boat-shaped or wedge shaped with
  bilateral symmetry and a raphe a longitudinal
  groove, observed as a line running the length of
  the diatom

http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
4
Centrales

• Round with radially symmetrical ornamentation.
• Some are triangular.
• Contain no raphe.

http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
5
Frustules
Siliceous Wall/Shell

• The Walls or Shells
• Siliceous shell has two sections, creates valves,
  that overlap each other similar to a lid on a
  box.
• Beautifully decorated in many variations

http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
6
Habitat

• Widespread in water
• Freshwater, Salt and Brackish water
• Benthic, Eutrophic, and Mesotrophic regions
• Standing or Running Waters
• Various temperatures
• pH range of 4 to 8

7
Feeding Habits

• Majority are autotrophic
• Some are heterotrophic
• Soil, algae, and natural sea water extracts
• Gained through absorption.
• Photosynthesis is source of energy
• Diatoms produce most of the worlds oxygen supply

8
Reproduction

• Asexual
• Most common usually binary fission
• Size of valves gradually decrease
• Sexual
• Fusion in many variations

9
Seasonal Patterns
10
Factors that Can Lead to the Decrease of Diatom
Population

• Competition with other species (i.e. other
  phytoplankton)
• Habitat
• Food
• Other resources (i.e silica)

11
Previous Lake Herman Data
12
Hypothesis

• As the temperature of the water and sunlight
  increases, the diatom population will also
  increase. This is due to the increase in
  photosynthesis among the diatoms.
• Therefore, I predict that diatoms will appear
  before melting and become diminished when the
  population of cyanobacteria is at high densities
  in Lake Herman. Diatoms will then increase in
  abundance again after the blooms of cyanobacteria
  have decreased.

13
Procedures

• Gathered water samples from March 23, 2001 to
  November 2, 2001 in a weekly/biweekly rotation.
• Samples gathered through grab sampling.
• pH levels, dissolved oxygen, temperature and
  dissolved phosphate levels were taken at the time
  of the grab sampling.
• Grab sample were examined to estimate diatom and
  other algae populations.
• Examinations were done by counting the diatoms
  and algae with use of a microscope.

14
Procedures cont.

• Used the Hach surface water testing kit to take
  pH, dissolved O2, temperature, and dissolved
  phosphate levels.
• Counted diatoms and algae by using
  Sedgwick-Rafter Slide cell that held 1mL of
  sample water at a time.
• Counted 3 mL of each sample.

15
Results
16
Diatom Population AndDissolved Oxygen
17
Diatom Population andAlgae Growth
18
Diatom Population and Temperature
19
Naviculoid(from a list of diatom genras)

• Microscope Picture

Drawing of Picture
http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
20
Achnanthales(from a list of diatom generas )
Drawing of Picture

• Microscope Picture

http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
21
Naviculoid(from a list of diatom genras)

• Microscope Picture

Drawing of Picture
http//www.umich.edu/phytolab/GreatLakesDiatomHom
ePage/groups/majorgroups.html
22
Diatom with Algae Clump
Example of what the algae clumps looked like with
diatoms present.
Blue-Green Algae Clump (Microcystis)
Diatom
23
Conclusion

• I conclude that the diatom response to increase
  in cyanobacteria was less than what was expected.
• Therefore I must partially reject my hypothesis.