96 ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Division Chrysophyta 

 Class Bacillariophyceae 

 Order Pennales 

 Family Surirellaceae 

 GENUS SURIRELLA Turpin, 1828 (fig. 42) 



MORPHOLOGY 



Cells generally are solitary and free floating, are linear elliptical or 

 ovate in valve view, have broadly rounded to subacute poles, and are 

 rectangular naviculoid, cuneate, or sigmoid in girdle view. Girdles are 

 smooth. Entire valve face may be in 1 plane, or it may be slightly spiral- 

 ly twisted. Each valve margin is keeled and contains a raphe having 

 central and polar nodules. Parallel costae are transverse. Fine striae 

 extend across valve face and are interrupted by a median longitudinal 

 pseudoraphe. One chromatophore is present. 



REPRODUCTION 



Protoplasts from 2 cells lying end to end unite to form an auxospore. 



OCCURRENCE 



The alga has a widespread distribution. 



ENVIRONMENTAL CONDITIONS 



Standard 

 Range Mean deviation 



Temperature degrees Celsius 0.0 - 37.0 



pH 3.7 - 10.0 



Dissolved oxygen milligrams per liter 2.5 - 18.4 



Specific conductance micromho 29 -35,000 



Total alkalinity milligrams per liter - 440 



Total hardness do 6 - 1,800 



Total nitrogen do .01- 41.0 



Total phosphorus do .0 - 4.0 



SPECIES INFORMATION 



Refer to Boyer (1927a). 



