Seagrass productivity: The effect of light on carbon uptake

摘要: Productivity, as estimated by 14C uptake, was determined a function of irradiance for six North American seagrasses (Thalassia testudinum Banks ex. Konig, Syringodium filiforme Kutz, Halodule wrightii Aschers., Halophila engelmanni Phyllospadix scouleri Hook and Ruppia maritima L. s.l.) from temperate, subtropical tropical environments. Light versus productivity curves were typical those aquatic plants. Seagrasses achieved high rates uptake (up to 17.31 mg C (g dry)−1 h−1) exhibited saturation irradiances (⩾ 40% surface irradiance). Within each environment half-saturation similar, indicating no competition light in the production systems various species. Between environments maximum changed differing irradiance. When normalized ambient irradiance, there differences rates, except plants Texas. In subtropics tropics where several species co-exist same seagrass bed, two types responses occurred, corresponding climax colonizer The difference response appeared initial sensitivity Productivity can be estimated, with certain limitations, measurements using equations Michaelis-Menten Steele.