122 ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Division Cyanophyta 

 Class Cyanophyceae 

 Order Hormogonales 

 Family Oscillatoriaceae 

 GENUS LYNGBYA Agardh, 1824 (fig. 55) 



MORPHOLOGY 



Cells are discoidal and adjoined at the flat faces into long trichomes. 

 Trichomes are unbranched, uniseriate, the same diameter from base to 

 apex, and contained in firm, conspicuous sheaths. Filaments are 

 straight, curved, or twisted and may be solitary or densely intertwined 

 into floccose masses. They may be free floating or epiphytic. 

 Heterocysts and akinetes are lacking. 



REPRODUCTION 



Reproduction is by hormogonia. 



OCCURENCE 



The genus is found commonly in eutrophic waters, and it is generally 

 indicative of hard water. It can occur in great numbers in eutrophic 

 lakes, where it remains distributed through the water column. It is 

 found in both the euplankton and tychoplankton. 



ENVIRONMENTAL CONDITIONS 



Standard 

 Range Mean deviation 



Temperature degrees Celsius 0.0 - 34.5 



pH 4.1 - 9.2 



Dissolved oxygen milligrams per liter .1 - 20.6 



Specific conductance micromho 24 -48,000 



Total alkalinity milligrams per liter - 478 



Total hardness do 3 - 2,000 



Total nitrogen do .01- 18.0 



Total phosphorus do .0 - 4.0 



SPECIES INFORMATION 



Refer to Gomont (1892a), Geitler (1932), and Prescott (1962). 



