The energy content of benthic invertebrates was estimated of two arid tropical sandy beaches, namely AlBirk and AlHorida, on the south eastern coast of the Red Sea, Saudi Arabia in the summer of 2007. This is the first study to deal with the benthic energy of such arid tropical beaches, using the relationship between body dimensions and wet weight to estimate biomass (and from this, ash free dry weight) as well energy content independently of species identifications. The energy values were generally lower than those in Temperate or Arctic zones. The average energy content at AlBirk and AlHorida beaches was 4 and 1.4 Kcal.m-2, respectively. AlBirk was dominated by Amphipoda, Bivalvia, Polychaeta, and Ostracoda, with energy values of 1.3, 1, 1, and 0.5 Kcal.m-2, respectively, while AlHorida was dominated by Polychaeta with a value of 0.9 Kcal.m-2. The differences between the two sites in terms of average wet biomass, ash free dry weight and energy per m2 were attributable to differences in wave energy, grain size and organic matter that led to the differences in abundance and dominance.
Key words: Benthic invertebrates, Abundance, Biometric conversion, Energy, Sandy beaches, Tropical
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