ZoBell — 134 — Marine Microbiology 



Parasitic and epiphytic fungi may occur on marine algae much more 

 extensively than indicated by the fragmentary literature on the subject 

 Such organisms are difficult to detect and identify even in properly col- 

 lected specimens. The distinguishing morphological structures of the 

 fungi are so minute and so intimately associated with the host tissue that 

 they may escape detection. In some cases they have been mistaken for 

 the fruit bodies of certain marine algae. For example, Kibbe (191 6) 

 described Chytridium alarium as a fungus parasitic on Alariafistulosa, but 

 Sparrow (1943) records that Kibbe mistook the cystidia of the alga for a 

 fungus. 



According to the literature summarized by Kibbe (191 6), Lemmer- 

 MAN named a marine fungus, Dothidella laminariae, which is parasitic on 

 Laminaria. Estee described Guignardia irritans, parasitic on Cystoseira 

 and Halidrys. Patouillard described Zignoella calospora, parasitic on 

 Castagnea. Patouillard and Hariot found Zignoella enormis on Stypo- 

 caulon. Reed described two ascomycetes, Guignardia ulvae on Ulva, and 

 Guignardia alaskana on Prasiola. Cohn described Chytridium poly- 

 siphoniae on Polysiphonia, Olpidium plumulae on Antithamnion, and 

 Olpidium entosphaericum on Hor?niscia. Fischer mentions Rhizo- 

 phydium dicksonii on Ectocarpus, Olpidium sphacellarum on Sphacelaria, 

 Olpidium tumefaciens on Ceramium, Olpidium bryopsidis on Bryopsis, and 

 Olpidium aggregatum on Cladophora. Besides these parasitic marine fungi 

 to which references are given by Kibbe (191 6), Sparrow (1943) lists 

 Rhizophydium gelatinosum, and Achlyogeton salinum, both of which are 

 parasitic on Cladophora, Olpidium lauderiae parasitic on Lauderia, Rhizo- 

 phydium marinum parasitic on Melosira, and Rozella marina parasitic in 

 the sporangia of Chytridium poly sip honiae. 



Sparrow (1936) suggests that the peculiar rhythms of blooming peri- 

 ods and distribution of pelagic diatoms which cannot be attributed to 

 hydrographic factors may sometimes be due to the activities of parasitic 

 fungi. There is accumulating evidence, but no conclusive proof, that 

 many of the diatoms and dinoflagellates which observers report are found 

 in ''poor condition " may have been parasitized. Diatoms parasitized by 

 Ecirogella perforans were observed by Sparrow (1934) to distort the 

 frustules sometimes so much as to suggest that the fungus had dissolved 

 the siliceous material and produced hypertrophy of the diatom cell. The 

 possibilities of parasitism, coupled with the importance of diatoms and 

 dinoflagellates as primary producers, invite early attention to this 

 problem. 



The wasting disease of Zostera marina which has depleted the eel grass 

 from hundreds of miles of coast in Europe and America may be due to a 

 fungus infection. Tutin (1934) believed Ophiobolus halimus to be the 

 causative agent. Renn (1936) failed to find any Ophioboliis-like fungi 

 associated with the rhizomes or leaves of diseased plants, but he did find 

 a species of Labyrinthula in all of the diseased plants which he examined. 

 The association of Ophiobolus (Halophiobolus) salinus, H. halimus, and 

 H. maritimus with eel grass has been reported by Barghoorn and Linder 

 (1944), who state that further research is required to ascertain whether 

 these species arc causative agents of the wasting disease, secondary in- 

 vaders, or merely saprophytic. 



The brown alga, Macrocyslis pyrifera, which is of considerable eco- 

 nomic importance, may be subject to epidemics of fungus infections. 

 Similarly, other commercially valuable marine algae may be affected by 



