conch, sea urchins, and some nudibranchs. The green sea turtle formerly 

 grazed heavily on the turtle grass, hence the name. It has been found, 

 however, that certain urchins grind up the seagrasses but do not appear 

 to digest them, and this may well apply to other animals which appear to 

 graze on them. 2) seagrasses serve as hosts for large numbers of 

 epiphytes which are grazed extensively, for example, by the mullets. 

 These epiphytes may be comparable in biomass with the seagrasses them- 

 selves. 3) seagrasses provide large quantities of detrital material 

 which serves as food for certain animal species and for microbes which 

 in turn are used as food by larger animals. 4) seagrasses provide 

 organic matter to initiate sulfate reduction and an active sulfur cycle. 

 5) seagrasses bird the sediments and prevent erosion. This also pre- 

 serves the microbial flora of the sediment and the sediment-water inter- 

 face. 6) seagrasses tend to collect organic and inorganic material by 

 slowing down currents and stabilizing the sediments. 7) the seagrasses 

 have a rapid rate of growth (up to 9 mm per day, average 2 to 4 mm per 

 day) and produce between 2.2 and 10 gm of dry leaf per m2 per day. 



The study also contains a brief comparison of Thalassia and Spartina 

 with respect to production of detritus. (A. A. -modified) 



Keywords: seagrasses, productivity, coastal ecosystems 



IV-F-2 



Phillips, R.C. 1960. Observations on the ecology and distribution of the 

 Florida seagrasses. Florida State Board of Conservation Marine Laboratory, 

 St. Petersburg, Professional Papers Series No. 2. 72 pp. 



In 1957, a program of seagrass research was initiated by the Florida 

 State Board of conservation. The initial work, which is described 

 in this report, consisted of studies in distribution, ecology, and 

 growth rates. 



Florida has over 3,000 miles of coastline whose extremes extend from 

 the tropical to the warm temperate zones. Natural physical forces 

 have created barrier islands and offshore keys with abundant shallow 

 quiet water conditions in many areas of the state which became favorable 

 habitats for the establishment and growth of submerged plants. Plants 

 constitute the basic link in the food chain and are the producing 

 group of organisms in the food pyramid. Among these plants, there are 

 four important seagrasses in Florida waters; namely, Thalassia 

 testudinum Konig, Syringodium fili forme Kutz (= Cymodocea manatorum 

 Aschers), Diplanthera wrightii Aschers (= Halodule wrightii Aschers), 

 and Ruppia maritima L. Two species of Halophila occur in Florida 

 (H. bail Ion is Aschers and H. engelmannii Aschers), but are not treated 

 extensively in this paper owing to infrequency of occurrence and 

 sparse abundance when found. 



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