Table 2.1. Benthic Algae Collected from Bay Sediments (2) and Beach Sands (4) in the 
Galveston Bay System. 
Green Algae 
Blue-green Algae 
Diatoms 
Bracteacoccus 
Anabaena 
Achnanthes (2) 
Characium 
Anacystis 
Actinoptychus (3) 
Chlamydomonas 
Aphanocapsa 
Amphora (3) 
Chlorosarcina 
Aphanothece 
•Coscinodiscus (10) 
Chlorosarcinopsis 
Calothrix 
•Cydotella (3) 
Chlorococcum 
Gloeocapsa 
Diatoma (1) 
Cylindrocystis 
Lyngbya 
•Diploneis (4) 
Eremosphaera 
Myxosarcina 
Epithemia (1) 
Gloeocystis 
Nostoc 
Eunotogramma (1) 
Hormidium 
Oscillatoria 
Mastogloia (1) 
Oedocladium 
Schizothrix 
Melosira (2) 
Pleurastrum 
Spirulina 
Navicula (4) 
Radiosphaera 
Synechococcus 
Nitzschia (9) 
Stichococcus 
Synechocystis 
Opephora (1) 
Tetracystis 
Xenococcus 
Pinnularia (1) 
Tetraedon 
Pleurosigma (4) 
Rhopalodia (2) 
•Skeletonema (1) 
Stenopterobia (1) 
Crvptophvtes 
Euglenpphytes 
Stephanodiscus (1) 
Cryptomonas 
Euglena 
Surirella (1) 
Synedra (1) 
(n) = number of species in genus, if given 
* = most abundant 
of algae were identified from Galveston Island beach sands, and 22 genera (56 species) of diatoms 
were identified from bay sediments (Table 2.1). The diatoms Coscinodiscus, Diploneis, Cydotella 
and Skeletonema were noted as being very abundant (2), the latter two genera also dominating the 
phytoplankton as noted previously. Diatoms were the main component of the benthic microflora in 
waters deeper than 0.5 m, while blue-green algae dominated the shallow water and tidal flats (3). 
Algal densities could not be related to depth, sediment type. Eh, pH or salinity. 
Macroalgae—There has been no survey of macroalgal types over the whole bay system. Several 
faunal surveys (9,13,24) noted that, where present, the macroalgae is represented by Enteromorpha, 
Ectocarpus, Dictyota, Sargassum, Polysiphonia and Gracilaria. The major study of macroalgae was 
limited to Galveston Island proper (46), finding 19 genera and 28 species over a two-year period 
(Table 2.2). The gulf shore community is composed of Cladophora, Bryocladia and Ceramium in 
summer and shifts to Enteromorpha, Bangia and Gelidium in winter. The bay shore community is 
barren in the summer and is primarily Enteromorpha and Ectocarpus during winter. The flora is 
considered depauperate relative to other Gulf estuaries. 
Submerged aquatic vegetation—Submerged aquatic vegetation is limited in areal extent. On the 
Trinity River delta, the submerged freshwater plants Vallisneria americana (tapegrass) and Sagit- 
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