In contrast, these authors found fragment techniques Inter-Simple Sequence Repeats [ISSRs] to reveal highly structured Hawaiian populations with a substantial range of both within- and among-population variation, with individual plants forming discrete clusters corresponding to geographic locality. Reproductive Biology The sexual life history of A. The thalli are also easily fragmented by wave action, and fragments have the potential to re-attach after 2 days Kilar and McLachlan, Skelton and South quote an autecological study of A.
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Acanthophora Species Description Acanthophora spicifera is a Rhodophycean alga with wide distribution throughout the tropics and subtropics Kilar and McLachlan, It occurs on a wide variety of substrata , from hard bottom, as an epiphyte on other algae, or as a free living drift alga. It is often a large component of drift algae biomass. From the holdfast, erect fronds begin to branch out.
The main branches have short, determinate branchlets that are irregularly shaped and spinose. Branchlets are hook-like, brittle and fragment easily under heavy wave action. Color is highly variable, and can be shades of red, purple, or brown Littler and Littler, It has a wide distribution in both tropical and subtropical habitats, occurring primarily in the tidal and subtidal zones.
It is found extensively on shallow reef flats throughout Florida, the Virgin Islands and Puerto Rico to depths of 22 meters, although it typically inhabits more shallow waters from 1 - 8 meters in depth Kilar and McLachlan, ; Littler and Littler Dead or dying specimens can be found smothering Thalassia testudinum beds. However, wave action is known to alter branching morphology depending on whether the alga inhabits a fore-reef or a back-reef habitat.
In one study performed in Panama, A. Abundance A. Locomotion Sessile. Fragments are carried and dispersed by local currents. Reproduction Sexual: A. Asexual: Fragmentation accounts for much of the distribution and standing crop of this species. Kilar and McLachlan showed that exported biomass of A. This equated to an estimated average of approximately kg per year. Turbulence in the fore-reef zone causes A.
Currents often transport fragments across seagrass meadows to the back-reef zone, where they snag on rocks, algae, or some other substratum. Higher currents tended to decrease the chances of snagging Kilar and McLachlan Approximately 2 days was required for A. However, in experimental plots Kilar and McLachlan , A. Taylor and Bernatowicz and Trono , based on the observation that A.
However, as the species is common throughout the topics and subtropics, its survival temperature range is thus significantly broader. Salinity Typical reef salinity in the Caribbean areas sampled for A. Tabb and Manning observed that densities of this species generally increased when salinity decreased, but also found that it tolerated higher salinity levels relatively well.
Other Physical Tolerances A. Competitors Acanthophora spicifera survival on reefs is enhanced when it co-occurs with dense aggregates of other algal species that are more tolerant of wave exposure and are able to retain water when exposed to air. One such beneficial species is Laurencia papillosa. In some Caribbean habitats, A. Predation upon A. An examination of the gut contents of dead turtles showed that they grazed tufts of A. In a study conducted by Russell and Balazs , A. Habitat Grows attached to rocks and oyster rubble in shallow 1 m areas of the Indian River Lagoon.
Elsewhere, it commonly inhabits reef flats where it attaches to hard bottoms, grows as an epiphyte on other algae, or is free living as drift algae. Activity Time An association refuge sometimes occurs when A. Kerr and Paul have shown that predation upon A. Though this species, as well as another invader, Hypnea musciformis, have both been shown to compete with native species in Hawaii, they have added to the overall productivity of the areas they inhabit Russell and Balazs Further, they have become a significant part of the diet for some fish species, and the green turtle, Chelonia mydas Russell and Balazs Rhodophyceae 4.
Ellison, A. Farnsworth, et al. Ecology 77 8 Ganesan, M. Indian Journal of Marine Sciences Jokiel, P. Marine Biology Kerr, J. Cnidaria, Alcyonacea Protects Halimeda spp. From Herbivory. Kilar, J. Ceramiales: Rhodophyta : Vegetative Fragmentation. Aquatic Botany Kilar J. Norris, J. Cubit, et al. Littler, D. Littler, K. Bucher et al. Smithsonian Institution Press, Washington D. Parekh, R. Doshi, et al. Russell, D.
ICES mar. Aquatic Botany 47 1 Tabb, D. Taylor, W. Distribution of Marine Algae About Bermuda. Bermuda Biol. Trono, G. Report by: K. Hill, Smithsonian Marine Station Submit additional information, photos or comments to:.
Vahl Fucus acanthophorus , J. Lamouroux Acanthophora thierryi , J. Lamouroux Chondria acanthophorara , C. Agardh Acanthophora orientalis , J. Agardh Acanthophora wightii , J.
Indian River Lagoon Species Inventory