Heterotrophy in Marine Diatoms 

 TABLE 1 



231 



Species of Marine Diatoms Tested for Heterotrophic Growth 

 Utilizing Glucose or Lactate^ 



Species Found Capable of 

 Heterotrophic Growth 

 Pennate 

 Amphora coffaeiformis (8 isolates) 

 Navicula incerta 

 Nitzschia angularis 

 Nitzschia filiformis 

 Nitzschia frustuluni (3 isolates) 

 Nitzschia laevis (2 isolates) 

 Nitzschia curvilineata 

 Nitzschia marginata 

 Nitzschia punctata 

 Nitzschia tenuissima 

 Nitzschia closterium (4 isolates) 

 Nitzschia thermalis 



Centric 



Cyclotella sp. 



Species Found Incapable of 

 Heterotrophic Growth 

 Pennate 

 Achnanthes brevipes 

 Amphipleura rutilans 

 Amphiprora paludosa 

 Amphora coffaeiformis (2 isolates) 

 Amphora lineolata 

 Navicula menisculus 

 Navicula sp. 



Nitzschia hybridaeformis 

 Nitzschia frustulum (3 isolates) 

 Nitzschia obtusa v. scalpelliformis 

 Nitzschia ovalis 

 Nitzschia sp. 

 Synedra affinis 

 Stauroneis amphoroides 



Centric 

 Chaetoceros pseudocrinitus (?) 

 Chaetoceros ceratosporum (?) 

 Chaetoceros pelagicus (?) 

 Chaetoceros (2 unidentified sp.) 

 Coscinodiscus asteromphalus 

 Cyclotella nana (3 isolates) 

 Cyclotella caspia 

 Melosira nummuloides 

 Melosira sp. 

 Skeletonema costatum 

 Thalassiosira fluviatilis 

 Unidentified (2 species) 



1 Some of these data have been published elsewhere (4). 



Necessity of an Organic Nitrogen Source for 

 Heterotrophic Growth 



All of the tests carried out and reported in Table I involved 

 media containing Tryptone in addition to the organic substrate 

 (except in the case of four species of centric diatoms that were 

 inhibited by Tryptone in the light ) . The nutritive value of Tryp- 

 tone for heterotrophic growth was assessed independently by 

 incubating heterotrophic species in the dark in media containing 



