1. Phillip L Treiber
Marine Botany – Dr. G
3/20/14
Microalgae
Collection and
Identification

2. Type: Marine Diatom
Chaetoceros danicus

3. Type: Marine Cennate Diatom
Common
Distinctive corkscrew chain of cells
The sample this was taken from a
plankton pull from Casco Bay, South
Portland on March 6th
, 2014
The chain is under 200 long microns
with an estimated 35 cells in the chain
Image taken at 40x magnification
Chaetoceros debillas
Figure 1. Both girdle and valve views of Chaetoceros debillas

4. Chaetoceros debillas
Figure 2. Both girdle and valve views of Chaetoceros debillas

5. Type: Marine Cennate Diatom
Chains straight and stiff. Only the
valve corners touch the cell next to it.
Setae seem fused for a short distance
and then split, but they are separate
Terminal setae thicker (not shown)
‘Long’ side of the cell is less than
30µm. “Short side less than 25µm
The sample this was taken from a
plankton pull from Casco Bay, South
Portland on March 6th
, 2014
Image taken at 40x magnification
Chaetoceros decipiens
Figure 1. Valve view of Chaetoceros decipiens in a chain

6. Type: Marine Pennate Diatom
Extremely common at all times of
year
Elongated cell with upturned ends
Solitary cells
The sample this was taken from a
plankton pull from Casco Bay, South
Portland on March 17thth
, 2014
Image taken at 40x magnification
Source: Carmelo and Hasle,
Identifying Marine Phytoplankton,
1997
Cylindrotheca closterium
Figure 1. Valve view of Cylindrotheca closterium

7. Type: Marine Pennate Diatom
Distinctive shape of cylinder with
spines extending from cylinder
Cells solitary
Chloroplasts numerous, but in small
granules
The sample this was taken from a
plankton pull from Casco Bay, South
Portland on March 6th
, 2014
Image taken at 40x magnification
Ditylum brightwellii
Figure 1. Valve view of Ditylum brightwellii

8. Ditylum brightwellii
Figure 2. Valve view of Ditylum brightwellii

9. Type: Marine Pennate Diatom
The sample this was taken from a
plankton pull from Casco Bay, South
Portland on March 6th
, 2014
Image taken at 40x magnification
Licmophora flabellata
Figure 1. Valve view of Licmophora flabellata

10. Type: Marine Pennate Diatom
The sample this was taken from a
plankton pull from Casco Bay, South
Portland on March 6th
, 2014
Image taken at 40x magnification
Licmophora flabellata
Figure 1. Valve view of Licmophora flabellata