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Ecology |
Plant Biology and, Ecology and Systematics, Cornell University, Ithaca, New York 14853-5908 USA; and Physical Ecology Laboratory, University of Northern British Columbia, Prince George, British Columbia, Canada V2N 4Z9
The dispersion and capture of differently shaped particles within a Zostera marina L. (eelgrass; Zosteraceae) bed were examined to understand submarine pollination and other dispersals. During periods of moderate flow in the canopy, the capture rate of "spherical" (the shape of ancestral pollen) and "filamentous" (the shape of eelgrass pollen) particles was greater for particles released at the top of the canopy (3.07 and 4.53% x 105 cm2 of collector; i.e., percentage of particles captured normalized to collector area) and greater for filamentous than for spherical particles (4.51% x 105 cm2 vs. 2.01% x 105 cm2). Estimates of the horizontal P (Joseph-Sendner diffusion velocity) and the vertical diffusivity (Gaussian K) of filamentous particles were small (P
4 x 104 m/s; K
104 m2/s) compared to theoretical values that do not consider plant canopies. These findings support the concept that eelgrass canopies modify the fluid dynamics (i.e., reduced turbulent mixing) within their canopies. These results indicate that 100010 000 Z. marina pollen are required to pollinate a single flower. Similarly, it was estimated that under some conditions, the probability of particle impaction on eelgrass vegetation approaches certainty. These results provide insight into the evolution of filamentous pollen and submarine pollination, as well as dispersal and other mass transport phenomena within macrophyte canopies.
Key Words: canopy flow dispersion mixing particle capture particle transport seagrass submarine pollination Zosteraceae Zostera marina
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