Benthic macroalgae as a dispersal mechanism for fauna: Influence of a marine tumbleweed
Holmquist JG. 1994. Benthic macroalgae as a dispersal mechanism for fauna: Influence of a marine tumbleweed. Journal of Experimental Marine Biology and Ecology. 180:235-251
Effective dispersal is problematic for benthic organisms without planktonic larvae; rafting and vertical migration are mechanisms that can potentially be employed by such fauna, but these strategies entail considerable predation risk as well as other disadvantages. Unattached, but non-floating, "drift" algae harbor large numbers of fauna and may serve as an alternative dispersal mechanism in some system. This paper reports field manipulations in Florida Bay, Florida, USA designed to determine (1) if such algae can disperse benthic animals, and (2) if dispersal efficiency varies as a function of two common substrata types: seagrass and bare sediment. A live immersion stain was used to mark faunal associates of Laurencia spp. algal clumps in situ. The fidelity of molluses, decapods, ophiuroids, and fishes to stationary algal clumps was then compared with the fidelity of these animals to clumps that were forced to tumble over a given distance with a blower apparatus; these experiments were performed over both sand and seagrass substrata. Measurements of frequency, spatial extent, and rate of algal drift were made to aid in assessing the potential importance of benthic algae as a dispersal mechanism. Algal clumps often rolled in a manner similar to that of terrestrial tumbleweeds; mark-recapture work showed algal clumps can move up to 0.5km/day and that algal drift is a frequent phenomenon. The algal masses were effective transporters of benthic fauna, including mobile shrimps and fishes; dispersal was more efficient over sand than over seagrass. Dispersal of fauna via this mobile habitat should entail lower risk than other adult dispersal stratagems such as vertical migration or rafting; this mechanism would be most advatageous for brooding species or those with limited planktonic phases. Differential fidelity to clumps tumbling across seagrass versus sand suggests that the algae could facilitate exchange of fauna between isolated seagrass patches. Abstract provided by author.
- Type
- Journal Article
- Authors
- Holmquist, J.
- Units
- BISC
- Keywords
- Algae, Algal clumps, Bare sediments, Benthic Fauna, Benthos, Dispersal, Drift Algae, Drift macrophyte, Ecology, Florida Bay, Laurencia spp., Macroalgae, Manatee grass, Marine tumbleweed, Mark-Recapture, planktonic larvae, Predation, Seagrass, Sediment, Shoal grass, Turtle Grass, Unattached algae