Epithemia
Epithemia spp. · Phytoplankton
Under the microscope · Photo: Petr Knotek / CC BY
How to identify Epithemia
- Under the microscope: curved, kidney or bean shaped diatoms with heavy crosswise ribs
- Often attached to plants and filamentous algae
- Contain tiny nitrogen fixing bodies inside the cell
- In the water: part of brown coatings on plants
Similar species
Cymbella is curved but lacks the strong ribs; Navicula is straight and boat shaped.
Profile
| Season | Summer and fall. |
|---|---|
| Starts | About 55 F and up |
| Light | Moderate to full light |
| Depth | Attached to surfaces |
| How it spreads or reproduces | Cell division |
| Habitat | On plants, rocks and filamentous algae in ponds, canals, springs and lake edges; hard, alkaline water. |
Why it matters in a lake
Close relatives in the genus Rhopalodia were proposed for merging into Epithemia in 2016, but the change is disputed and most labs and databases still use Rhopalodia. Their nitrogen fixing partners let them thrive when nitrogen is low.
Where it is found
- Idaho: Common
- Oregon: Common
- Wyoming: Common
Classification
| Kingdom | Chromista |
|---|---|
| Phylum | Bacillariophyta |
| Class | Bacillariophyceae |
| Order | Rhopalodiales |
| Family | Rhopalodiaceae |
| Scientific name | Epithemia spp. |
Fragilaria
Cyclotella
Asterionella
Navicula
Aulacoseira
Ulnaria (Synedra)
Nitzschia
Stephanodiscus
Tabellaria
MelosiraNeed a hand?
Want to know what is in your water?
Lab counts of the algae in your lake show what is growing, how much and whether a bloom is coming.
Idaho / Wyoming (208) 501-4531Oregon (541) 280-0596