Study of the Ria Formosa ecosystem: benthic nutrient remineralization and tidal variability of nutrients in the water

✍ Scribed by Manuela Falcao; Carlos Vale

• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 805 KB
• Volume: 207
• Category: Article
• ISSN: 1573-5141
• DOI: 10.1007/bf00041450

✦ Synopsis

Exchange of nutrients across the sediment-water interfaces of Ria Formosa was studied in the laboratory. In the field, water samples were collected (i) fortnightly, at low and high tide over one year, and (ii) semi-diurnally, over three neap-spring tidal cycles in winter. Results from both laboratory experiments and field collection were quite variable. Higher liberation rates of silicates, phosphates and ammonium occurred in chambers whose bottom was formed by mixtures of mud and sand covered by vegetation with clams. The bottom took up nitrates from the overlying water. Nutrient variations in the lagoon water were controlled both seasonally and tidally. Higher concentrations of silicates were found at low tide independently of the season; phosphates in spring/summer at low tide; nitrates in winter/spring at high tide. Tidal flushing appears to be an important removal-mechanism in this lagoon.