centimeters of water between the sediment and the undersurface of the ice. 

 The odor of hydrogen sulphide, and subsequent tests with an oxygen probe, 

 showed this water to be anoxic. 



71. McROY, C.P., "Standing Stocks and Other Features of Eelgrass, Zoetera 

 mavina. Populations on the Coast of Alaska," Journal of the Fishevies 

 Research Board of Canada, Vol. 27, No. 10, Oct. 1970, pp. 1811-1821. 



Eelgrass populations were sampled from southeast Alaska to Bering Strait. 

 Those in Kinzarof and Izembek lagoons on the Alaska Peninsula had the highest 

 standing stocks (mean, 1,510 grams dry weight per square meter); populations 

 in Calder Bay in southeast Alaska had the lowest (65 grams dry weight per 

 square meter). Caloric content of eelgrass averaged 4,211 calories per gram 

 in the leaves and 3,571 calories per gram in the roots and rhizomes. The con- 

 centration of chlorophyll a in eelgrass had a mean of 0.513 milligram per 

 gram fresh weight with one exception. Population densities were high in 

 Kinzarof and Izembek lagoons (mean, 4,576 turions per square meter) and low in 

 other sample areas (599 turions per square meter). Flowering plants made up 3 

 to 4 percent of the total population. Mean leaf length varied from 13 to 48 

 centimeters and width from 2.4 to 5.1 millimeters. The differences in the 

 eelgrass populations appeared to be related to local conditions rather than a 

 large geographical gradient. 



72. McROY, C.P., and GOERING, J. J. , "Nutrient Transfer Between the Seagrass 

 Zostera marina and its Epiphytes," 'Nature, Vol. 248, No. 5444, Mar. 1974, 

 pp. 173-174. 



The production of leaf epiphytes on Zostera rmrina may be indirectly sus- 

 tained by nutrients in the sediments. The transfer of nitrogen and carbon was 

 measured using laboratory techniques and controls. Results indicate a direct 

 transfer of carbon and nitrogen from Z. marina to its epiphytes on the leaves, 

 showing a symbolic relationship. Nutrients are likely absorbed by the root- 

 rhizome system from the soil and distributed to all parts of the plant. 

 Epiphytes probably absorb nutrients that are leached through leaves. 



73. McROY, C.P., and HELFFERICH, C. , eds., Seagrasses Ecosystems: A Scientific 

 Perspective, Vol. 4, Marcel Dekker, Inc., New York, 1979. 



The report provides recommendations for research and includes background 

 notes. These constitute a framework for an interdisciplinary study on 

 seagrass ecosystems. Subject areas considered were productivity-physiology, 

 systematic ecology, decomposition, consumer ecology, and oceanography. It was 

 the opinion of these scientists that the significance of the overall contri- 

 bution of seagrass ecosystems to the ecology of the ocean cannot be adequately 

 evaluated on the basis of available knowledge. The evidence emphasizes the 

 need to document and understand the role of seagrass ecosystems before the 

 pressures of an overpopulated world's technological expansion unwittingly 

 destroy the seagrass meadows. 



74. McROY, C.P., and PHILLIPS, R.C., "Supplementary Bibliography on Eelgrass, 

 Zostera marina," Special Scientific Report, U.S. Fish and Wildlife 

 Service, Washington, D.C., No. 114, Jan. 1968. 



This bibliography lists 204 references on eelgrass to supplement an 

 earlier list issued in 1964 (see Phillips, 1964). 



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