1. Joseph Frias Chris Smith
Diatoms
Joseph Frias
Chris Smith

2. Characteristics of a Diatom
Photosynthetic
Unicellular although they can form colonies
Yellow-Brown color in life which is a result of photosynthetic pigments chlorophyll A and C carotenoids
Shell of Sílvia called a frustule
Most important primary producer on Earth

3. Didymosphenia geminata
Common name
Didymo
Rock snot
Valves large
Headpole capitate
Stigmata 2-5
Apical porefield present
Distal raphe deflected

4. Didymosphenia geminata
Location and habitat
Freshwater diatom , it is a type of single celled algae that lives attached to rocks on the bottom of streams, rivers and lakes
Thrives in clear warm nutrient poor water.
Traditional found in the northern hemisphere including northern parts of North America, Europe and Asia.
In the last 20 Years occurrences have become common in the northeastern US.
The species can now be found in over 18 states and three Canadian Provinces.

5. Didymosphenia geminata
How to identify/ structure
Resembles fiberglass insulation , or wet toilet paper
Generally light tan or brown in color
Stalks forming long white strands
Attaches to rock or plants
Reproduction
Vegetative Cell division
Feeding
Producer
Uses photosynthesis to make its food

6. Thalassiosira weissflogii
Unicellular microscopic algae
Found in Marine environments and inland watershed
Location/ habitat
Widespread European and Asian coastal waters
Inland rivers and Reservoirs In North America South America Hawaii and the Samoan Islands
Occurs in freshwater brackish And marine habitats especially those with salinities about 5%
Valves flat
Areolae fine
Prominent rimoportula on valve margin
Valves are flat, with short mantles. Areolae are fine. A single, prominent rimoportula is present on the valve margin.

7. Thalassiosira weissflogii.
How to identify/ structure
Thalassiosira weissflogii is a short cylinder in shape and varies in size from 4 to 32 µm in diameter.
It tends to be larger in winter, typically 15 µm in diameter, but smaller in summer (5 µm).[5] It occurs both singly and in groups and may be embedded in a gelatinous matrix.
Reproduction
Reproduction in Thalassiosira weissflogii can be by either asexual or sexual means. The asexual phase involves cell division with each of the new individuals receiving one of the valves. Large individuals can also reproduce sexually.
Feeding
Producer
Uses photosynthesis to make its food

8. Thalassiosira pseudonana
Thalassiosira pseudonana is a species of marine centric diatom.
It was chosen as the first eukaryotic marine phytoplankton for whole genome sequencing.
Location/habitat
typically found in freshwater and coastal brackish habitats
considered widespread.

9. Thalassiosira pseudonana
How to identify/ structure
This diatom can occur singly or in chains up to 6 cells long.
It typically exhibits a ring of fultoportulae around the edge of the valve
Reproduction
Sexual and asexual
Sexual reproduction has never been observed
Feeding
Producer
Uses photosynthesis to make its food

10. Phaeodactylum tricornutum
Structure
Unlike most diatoms P. tricornutum can grow in the absence of silicon, and it can survive without making silicified frustules.
It grows rapidly and storage lipids constitute about 20-30% of its dry cell weight under standard culture conditions.
Feeding Strategies
Producer
Uses photosynthesis to make its food

11. Phaeodactylum tricornutum
Location/Habitat
P. tricornutum can exist in different morphotypes, and changes in cell shape can be stimulated by environmental conditions.
This feature can be used to explore the molecular basis of cell shape control and morphogenesis.
found in a diverse array of marine environments including pelagic and benthic habitats P. tricornutum is known to tolerate a wide range of salinities and one of the few known diatom species capable of living without forming a silica shell
Reproduction
Another peculiarity is that during asexual reproduction the frustules do not appear to become smaller.
This allows continuous culture without need for sexual reproduction.

12. Ditylum brightwellii Structure Feeding Strategies
It is a unicellular photosynthetic autotroph that has the ability to divide rapidly and contribute to spring phytoplankton blooms
Feeding Strategies
Producer
Uses photosynthesis to make its food

13. Ditylum brightwellii Location/Habitat Reproduction
D. brightwellii is found in all global oceans except in polar waters.
Genetically distinct populations were observed over the course of a spring bloom in Puget Sound
Reproduction
D. brightwellii reproduces primarily asexually, creating clonal lineages.
Vegetative cells are capable of enlargement and may also produce resting spores.