The type of organic material found in a drift line undoubtedly accounts, 

 in part, for the growth response of colonizing species. Algae, one of the 

 principal components of oceanic drift lines, generally has a relatively high 

 carbon-nitrogen ratio (around 15:1) and may supply plants with usable nitro- 

 gen, which is usually the limiting factor in coastal environments. Algal 

 cells, which are much more absorbent than higher plant cells due to a lack, of 

 lignin, are also able to retain large amounts of moisture, which is available 

 to colonizing species. 



On the other hand, Arrmophila breviligulata, the principal component of 

 storm drift piles, has a high carbon-nitrogen ratio (greater than 75:1) and 

 may supply less nitrogen to colonizing plants. 4 rrvr.ophi.la breviligulata 

 rhizomes are extremely wiry with high concentrations of lignin, and aggregates 

 of this species are very poor in moisture retention. The general nucrient 

 status of bay drift material is unknown, but because of its texture it appears 

 at least to retain greater amounts of moisture than storm drift plies. 



To determine the growth response of Arrmophila breviligulata to different 

 types of drift material, an experiment was designed in which fragments, 

 planted with different types of organic material, were measured throughout 

 the growing season. A wooden frame was constructed on a washover fan with 

 four 1- by 1.5-metei. compartments. Each compartment was excavated to a depth 

 of 20 centimeters. Twenty-five genetically identical Arrmophila breviligulata 

 fragments were placed horizontally on the surface. Three compartments were 

 covered with 15 centimeters of drift material (Aecophyllum-algae, Arrmophila 

 breviligulata debris, or bay drift material), and one was filled, with sand. 

 Each treatment was covered with approximately 5 centimeters of sand. 



AwmoDhila breviligulata is known to grow best in areas of sand accumula- 

 tion. A fifth treatment was established in which a metal barrel with its 

 bottom removed was placed over 38 tillers in an accreting area and filled with 

 sand. Measurements were made of Arrmophila breviligulata tillers that grew 

 through 90 centimeters of sand. 



The tiller number per treatment, the mean leaf length per tiller, and the 

 length of the longest leaf of each tiller were recorded between 12 June and 

 27 August 1978 (Tables 37, 38, and 39). 



Initially, the greatest number of tillers were produced in the Arrmophila 

 breviligulata debris treatment, reflecting the presence of additional frag- 

 ments among the drift material itself (Figs. S2, and 87; Table 37). After 

 early July, however, the algal and 90-centimeter burial treatments produced 

 greater numbers of axes per treatment. Throughout the susaser, the treatment 

 without drift consistently produced fewest axes. The mean longest leaf for 

 each tiller was calculated for each treatment (Table 38; Fig. 88). Again, the 

 algal and 90-centimeter burial treatments produced the best growth. Although 

 the mean longest leaf lengths for these two treatments were not significantly 

 different (P > 0.05), they both differed from all other treatments (P < G.01). 

 Treatments with bay drift material or sand did not differ significantly from 

 one another (P > 0.05). 



Finally, the range of longest leaf length per tiller for each treatment 

 was also recorded to take into account the fact that healthy treateents are 

 continually producing new axes, which initially decreases mean leaf length 



144 



