Environmental Microbiology of Aquatic and Waste Systems

13 4 6 Ecology of Microorganisms in Saline Waters (Seas and Oceans)

many maritime countries as a source of food, for indus-
trial applications and as a fertilizer. Nori (Porphyra
spp.), a Japanese red seaweed, is very popular in the
Japanese diet, has a high protein content (25–35% of
dry weight), vitamins (e.g., vitamin C), and mineral
salts, especially iodine. Industrial utilization is at pres-
ent largely confined to extraction of phycocolloids,
industrial gums classified as agars, carrageenans, and

alginates. Agars, extracted from red seaweeds such as

Gracilaria , are used in the food industry and in labora-

tory media culture. In addition, some tuft-forming blue-

green algae (e.g., the poisonous Lyngbya majusculac)

are sometimes considered as seaweeds.

Seaweeds grow in marine environments, where there

is sunlight to enable them carry out photosynthesis.

Many of them contain air vacuoles to aid them in

Fig. 6.7 Ascospores of fungi growing on wood in the marine
environment. Note the structures for floatation and/or attach-
ment. Ascospores of (a) Amylocarpus encephaloides, (b) Arenario­
myces majusculus, (c) Carbosphaerella leptosphaerioides,

(d) Crinigera maritima, (e) Dryosphaera navigans, (f) Dryo­

sphaera tropicalis, (g) Nimbospora bipolaris and (h) Nimbospora

effusa; (i) conidia of Cirrenalia pseudomacrocephala (From

Prasannarai and Sridhar 2001. With permission)