Seasonal growth of the coral reef macroalga Dictyosphaeria cavernosa (Forskål) Børgesen and the effects of nutrient availability, temperature and herbivory on growth rate

摘要: Abstract The green alga Dictyosphaeria cavernosa (Forskal) Borgesen competes with corals for space on the slopes of patch and fringing reefs in Kane'ohe Bay, O'ahu, Hawai'i. Macroscopic algae rarely occur pristine coral reef slopes, but are increasingly common at sites anthropogenic nutrient input overfishing. A field study D. growth rates indicated that, absence grazing, an annual cycle occurs maximum fall minimum spring. This pattern corresponded more closely to changes water temperature than irradiance or column concentrations, yet laboratory experiments showed that do not vary within range Bay habitats. Enrichment conducted outdoor tanks supplied running seawater is nitrogen-limited levels measured Bay. Inorganic nitrogen phosphorus significantly higher enclosed spaces chambers created by thalli adjacent column. It hypothesized regeneration from sediments beneath thalli, and/or excretion animals inhabiting these contribute elevated levels. Nutrient appear be dependent, seasonal availability may explain observed .