Fortnightly light and temperature variability in estuarine intertidal sediments and implications for microphytobenthos primary productivity

摘要: Photosynthetically active radiation (PAR) and temperature were measured continuously at the surface of estuarine intertidal sediments in Tagus estuary, Portugal, along two spring-neap tidal cycles. PAR strongly conditioned by periodic inundation, with large abrupt variations occurring during flooding ebbing. levels reaching sediment decreased very rapidly to zero or low values most daytime immersion. Inundation high tide had general effect attenuating amplitude daily fluctuation, incoming water usually warmer than night early morning cooler day. The progression emersion resulted a clear fortnightly variation total surface, while both mean diurnal periods failed exhibit well-defined periodicity. obtained results indicate that environment is dominated, sub-seasonal time scales, periodicity irradiance conditions favourable for benthic photosynthesis.