Chapter 3 



I 



Ecology of Algae, Protozoa, Fungi 

 and Viruses 



E. J. Ferguson Wood 



have been asked to review the situation in marine microbial 

 ecology as it is evinced by the papers we have heard, and as a 

 reviewer, my own idiosyncracies may intrude. I shall not hesitate 

 to call on ideas I received in other sessions or in post-sessional 

 discussions. This review will not absolve you from tlie necessity 

 of reading the papers. As our field is so wide and important, it 

 proved impossible in the time allotted to the session to cover 

 the field completely, so the ciliates and rhizopods were completely 

 omitted, while the small, naked flagellates have not received 

 justice. The ciliates, except for the Tintinnids, are a sadly ne- 

 glected group, which is frequently numerous, almost always 

 present in the phytoplankton and in benthic environments, and 

 can grow and multiply under a wide range of conditions including 

 redox potentials from —0.25 V to +0.45 V. They are voracious 

 scavengers, but from the few records I have seen, and from my 

 own observation, they seem to be rejected from the food chain. 

 Rhizopods also are probably more important than is recognized. 

 They can frequently be cultured from plankton samples, es- 

 pecially neritic ones. 



COMPOSITION OF THE PHYTOPLANKTON 



Braarud (2) gives to the macroscopic, benthic algae, 2 per 

 cent of the area of the oceans, and this seems reasonable when 

 we consider that the macroscopic algae are practically confined, 

 apart from the Sargasso Sea, to a strip along the shore line in 

 temperate waters, with incursions into boreal regions, while 

 in the tropics the dominant macroscopic algae are the corallines. 



In tropical waters the smaller flagellates are relatively im- 



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