75. McROY, C.P., BARSDATE, R.J., and NEBERT, M. , "Phosphorus Cycling in an 

 Eelgrass {Zosteva mavina L. ) Ecosystem," Limnology and Oeeanogvaphy , 

 Vol. 17, No. 1, Jan. 1972, pp. 58-67. 



Uptake and excretion of phosphorus by roots and leaves of eelgrass 

 iZosteva mavina) were dependent on the orthophosphate concentration of the 

 medium. In a tidal pool dominated by eelgrass, the interstitial reactive 

 phosphorus concentrations of the sediments were as high as 75 microgram atoms 

 per liter. The plants absorbed 166 milligrams of phosphorus per square meter 

 per day and excreted 62 milligrams of phosphorus, per square meter per day 

 into the water. An amount equivalent to about 41 percent of the reactive 

 phosphorus excreted, or 3 metric tons of phosphorus, per day was exported from 

 the lagoon into the Bering Sea. These results open a new pathway to the phos- 

 phorus cycle for some estuaries. 



76. McROY, C.P., GOERING, J.J., and CHANEY, B., "Nitrogen Fixation Associated 

 with Seagrasses," Limnology and Oeeanogvaphy, Vol. 18 No. 6, Nov. 1973, 

 pp. 998-1002. 



The nitrogen fixing of three species of seagrasses, Thalassia testudinum 

 and Syvingodium filiforme from Florida and Zosteva mavina from North Carolina 

 and Alaska, was examined using the acetylene reduction technique. Rates of 

 nitrogen fixation were extremely low or undetectable. The results do not 

 support the generalization of others that this process supplies the nitrogen 

 required for the high productivity of seagrasses. 



77. McROY, C.P., et al. , "Survey of Macrophyte Resources in the Coastal Waters 

 of Alaska," Report No. R-71-6, University of Alaska, Institute of Marine 

 Science, College, Alaska, May 1971. 



This study provides (a) a quantitative assessment of natural stocks of 

 marine macrophytes (seaweeds and seagrasses) in the coastal water of Alaska, 

 (b) an evaluation of the commercial value of macrophytes from data on 

 abundance and chemical composition, (c) a reference herbarium of marine macro- 

 phytes, and (d) a compilation of data from literature on the chemical composi- 

 tion of Alaska marine macrophytes. The effort during the first year of study 

 was directed toward the development of quantitative survey techniques. The 

 significance of the research is to provide the background for the development 

 of a new industry in Alaska. 



78. MENZIES, R.J., ZANEVELD, J.S., and FRATT, R.M. , "Transported Turtle Grass 

 as a Source of Organic Enrichment of Abyssal Sediments Off North 

 Carolina," Beep Sea Reseavah, Vol. 14, Pergamon Press, Ltd., Great 

 Britain, Feb. 1967, pp. 111-112. 



The finding of a considerable amount of turtlegrass at abyssal depths off 

 North Carolina and at bathal depth off Florida suggests seagrass as a source 

 of organic nourishment for the deep-sea floor. Turtlegrass does not grow in 

 the Carolinas but is abundant in southern Florida, Bermuda, and the Bahamas, 

 which indicates that the grass is distributed by the Gulf Stream rather than 

 simple offshore transport. 



79. MEYERS, S.P. , et al. , "Thalassiomycetes VII. Observations on Fungal 

 Infestations of Turtle Grass, Thalassia testudinyjn Konig., " Bulletin of 

 Mavine Science, Vol. 15, No. 3, Sept. 1965, pp. 548-564. 



Seasonal studies of fungal infestation of turtlegrass (Thalassia testu- 

 dinion) in Biscayne Bay, Florida, revealed a wide range of foliicolous fungi 



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