Specimen #1: Cosmarium sp., Green Algae
Figure 1:
Cosmarium sp. at 1000X Magnification
Using a Light Microscope. Although it appears to be cell in the process of
mitosis, this organism is actually a single cell with a deep division known as
the isthmus and sinus. The green portions in each semi-cell are the chloroplasts, the photosynthesis factory. This particular specimen has peculiar tubules, perhaps
either pseudopodia or cilia-like structures, projecting out into the
surrounding environment from the plasma membrane that is not present in any of
the Cosmarium species shown in the
website used to identify this specimen.
Name: Cosmarium
sp.
Common Name: Green Algae
Phylum: Charophyta
Class: Zygnemophyceae
Order: Desmidiales
Family: Desmidiaceae
Collection Date: August
23, 2016
Habitat:
These microscopic algae mainly reside in acidic, oligotrophic, aquatic
environments. However, they can occasionally be found in subaerial or in basic,
eutrophic waters.
Location: James
H. Barrow Field Station Duck Pond
Description: Microscopic
algae of the order known as Zygnematales, commonly known as desmids or green
algae. It is a unicellular placoderm in the order of Charophyceae. A placoderm
has cells that are deeply divided in the middle. The two semi-cells are rounded
when views from the front and flattened, oval, or elliptic when viewed from the
side. The older half of the cell wall secretes mucilage. The mucilage swells as
it absorbs water and propels the cell forward. The cell wall may be smooth with
pores or ornamented with granules, pits, or warts. The vegetative cells usually
do not have spines. Each semi-cell has at least one central chloroplast. They
sometimes produces thick-walled resting cells. They undergo asexual
reproduction via cell division.
Key Used:
Baker, A.L. et al. 2012. Phycokey -- an image based
key to Algae (PS Protista), Cyanobacteria, and other aquatic objects.
University of New Hampshire Center for Freshwater Biology.
http://cfb.unh.edu/phycokey/phycokey.htm 4 Sep 2016.
Keying Steps:
Introduction Page:
Clicked on “Charophyceae (plant ancestors)”
Charophyceae Page:
Clicked on “Desmids”
Desmids Page: Clicked on
“Placoderm desmids (two wall halves)”
Unicell Desmids Page:
Clicked on “Placoderm desmids (two wall halves)”
Placoderm Desmids Page:
Clicked on “Cosmarium”
Specimen #2: Pyramimonas sp., N/A
Figure 1: Pyramimonas
sp.
at 400X magnification. This specimen was killed using Potassium chloride so a
picture could be taken. Prior to killing it, this specimen was using its many
flagella to move in the direction of the flagella. The left-hand picture is of
the specimen so that its eyespot is visible. The eyespot (red spot on top-left) was brown prior to killing the specimen, but has since turned red in
color. Other structures that are visible is the single chloroplast (Brown
circle in the middle-top of the cell). The right-hand picture shows off the
multiple flagella possessed by the specimen. These flagella are pronged so that
each has two tips.
Name: Pyramimonas sp.
Common Name: N/A
Phylum: Chlorophyta
Family: Pyramimonadaceae
Collection Date: September
7, 2016
Habitat:
Mostly marine in polar seas, with some freshwater species.
Location: A
stagnant pond alongside Brosius Road in Ohio.
Description: Flagellated
Unicells, oval, varying in size by an order of magnitude, 5 – 50 um, radially
symmetric with multiple flagella (4,8,16) arising from an apical pit. In some
instances the flagella have scales that vary with species and
habitat. If four or eight flagella are present there is one large chloroplast
containing a large pyrenoid. One to two eyespots are common as well
as a vacuole in freshwater species.
Key Used:
Baker, A.L. et al. 2012. Phycokey -- an image based
key to Algae (PS Protista), Cyanobacteria, and other aquatic objects. University
of New Hampshire Center for Freshwater Biology.
http://cfb.unh.edu/phycokey/phycokey.htm 4 Sep 2016.
Keying Steps:
Introduction Page:
Clicked on “Greens (Chlorophyceae)”
Greens (Chlorophyceae)
Page: Clicked on “Unicell Greens (Chlorophyceae)”
Unicell Greens Page:
Clicked on “Flagellated Unicells”
Flagellated Unicells
Page: Clicked on “Pyramimonas”
Algae Links:
Ohhh, nice flagella pic!
ReplyDelete