Effects of Macroalgal Zonation on a Reef Flat
Introduction
Tropical island reef flats serve as habitats for a diverse range of organisms. Among these organisms is an abundance of macroalgae. Macroalgae may even be numerous enough to comprise most of the benthic area near a reef (Carpenter 1986, Villaça et al. 2010, Hay 1981). The large presence of macroalgae corresponds to a large role as primary producers (Carpenter 1986). Thus, these organisms can play an important part in marine food webs.
Aside from the effects of herbivores, macroalgae distribution may be affected by other environmental factors (Marques et al. 2006, Villaça et al. 2010). Physical factors that affect macroalgae include desiccation, salinity, and temperature shifts (Tsuda 1977, Villaça et al. 2010). As autotrophic organisms, differing pH levels and oxygen, nitrate, and phosphate concentrations could possibly play an important role in their distribution. Their specific location on the reef flat might also be significant if varying wave actions affect algal growth. Aside from wave action, the lack of attachment structures that can be used to grow on sand may limit the distribution of some species (Tsuda 1977).
Furthermore, distributions could be unique to differing groups of macroalgae. This study focuses on three important macroalgal groupings: Rhodophyta, Chlorophyta, and Heterokontophyta. Rhodophyta, or red algae, is a relatively uniform group that is generally characterized by red pigments and a lack of motile cells (Chapman 1964, Drew 1951, Trainor 1978, Solomon et al. 2008). The cell walls of Rhodophyta are commercially important in the production of gelling agents (Trainor 1978, Solomon et al. 2008). Chlorophyta, or green algae, contain pigments that are nearly identical to those of higher plants, use starch as their main storage agent, and have cellulose in species that have cell walls (Chapman 1964, Iyengar 1951, Trainor 1978, Solomon et al. 2008). Heterokontophyta mostly consists of the brown algae. These brown pigmented
Tropical island reef flats serve as habitats for a diverse range of organisms. Among these organisms is an abundance of macroalgae. Macroalgae may even be numerous enough to comprise most of the benthic area near a reef (Carpenter 1986, Villaça et al. 2010, Hay 1981). The large presence of macroalgae corresponds to a large role as primary producers (Carpenter 1986). Thus, these organisms can play an important part in marine food webs.
Aside from the effects of herbivores, macroalgae distribution may be affected by other environmental factors (Marques et al. 2006, Villaça et al. 2010). Physical factors that affect macroalgae include desiccation, salinity, and temperature shifts (Tsuda 1977, Villaça et al. 2010). As autotrophic organisms, differing pH levels and oxygen, nitrate, and phosphate concentrations could possibly play an important role in their distribution. Their specific location on the reef flat might also be significant if varying wave actions affect algal growth. Aside from wave action, the lack of attachment structures that can be used to grow on sand may limit the distribution of some species (Tsuda 1977).
Furthermore, distributions could be unique to differing groups of macroalgae. This study focuses on three important macroalgal groupings: Rhodophyta, Chlorophyta, and Heterokontophyta. Rhodophyta, or red algae, is a relatively uniform group that is generally characterized by red pigments and a lack of motile cells (Chapman 1964, Drew 1951, Trainor 1978, Solomon et al. 2008). The cell walls of Rhodophyta are commercially important in the production of gelling agents (Trainor 1978, Solomon et al. 2008). Chlorophyta, or green algae, contain pigments that are nearly identical to those of higher plants, use starch as their main storage agent, and have cellulose in species that have cell walls (Chapman 1964, Iyengar 1951, Trainor 1978, Solomon et al. 2008). Heterokontophyta mostly consists of the brown algae. These brown pigmented
References: RC. 1986. Partitioning herbivory and its effects on coral reef algal communities. Ecological Monographs 56(4):345-364. Chapman VJ. 1964. The Algae. London: Macmillan and Company Limited. 472 p. Drew KM. 1951. Rhodophyta. In: Smith GM, editor. Manual of phycology. New York: The Ronald Press Company. p. 21-67. Hay ME. 1981. Herbivory, algal distribution, and the maintenance of between-habitat diversity on a tropical fringing reef. The American Naturalist 118(4):520-540. Iyengar MOP. 1951. Chlorophyta. In: Smith GM, editor. Manual of phycology. New York: The Ronald Press Company. p. 21-67. Marques LV, Villaça R, Pereira RC. 2006. Susceptibility of macroalgae to herbivorous fishes at Rocas Atoll, Brazil Solomon EP, Berg L, Martin D. 2008. Biology. Belmont (CA): Thomson Brooks/Cole, p. 544-546. Trainor FR. 1978. Introductory Phycology. New York: John Wiley & Sons, Inc.; 525 p. Tsuda RT. 1977c. Zonational patterns of the Phaeophyta (brown algae) on Guam’s fringing reefs Villaça R, Fonseca AC, Jensen VK, Knoppers B. 2010. Species composition and distribution of macroalgae on Atol das Rocas, Brazil, SW Atlantic