|Temporal and spatial variability of sedimentary organic matter in sandy beaches on the Northwest coast of the Iberian Peninsula|
Incera, M.; Cividanes, S.P.; Lastra, M.; López, J. (2003). Temporal and spatial variability of sedimentary organic matter in sandy beaches on the Northwest coast of the Iberian Peninsula. Est., Coast. and Shelf Sci. 58(Supplement 1): 55-61
In: Estuarine, Coastal and Shelf Science. Academic Press: London; New York. ISSN 0272-7714, more
|Authors|| || Top |
- Incera, M., more
- Cividanes, S.P.
- Lastra, M.
- López, J.
Temporal and spatial changes in sedimentary organic matter have been studied in several localities of the northwest coast of Spain. Biochemical composition of the sedimentary organic matter was studied in August and September 1997 in 10 beaches subjected to a different exposure degree to the wave action. Temporal variations in main biochemical classes were investigated in two of them (the more exposed and the more sheltered) over a 1-year period from January 1997 to January 1998 every 3 months. Sediment samples for the analysis of lipids, proteins and carbohydrates were collected at three tidal levels: high, medium and low, when the tide was on the ebb. Biochemical compounds concentrations were significantly higher in the sheltered beaches than in the exposed ones. The low hydrodynamic conditions of the sheltered beaches favour a high accumulation of sedimentary organic matter. There were significant differences among seasons and tidal levels. The biopolymeric carbon (BPC, i.e. the sum of lipid, protein and carbohydrate carbon) was dominated by proteins, followed by lipids and carbohydrates, pointing out the no limitation for heterotrophic metabolism in intertidal sediments. The exposure degree to the wave action was calculated by means of the beach slope. The relation between this parameter and the biochemical compounds showed that localities with low slopes (i.e. sheltered beaches) were related to high concentrations of lipids, proteins and carbohydrates and vice versa. The three biochemical classes showed different trends with time and changes were more pronounced in the sheltered beach than in the exposed one. These results could be explained by the influence of allochthonous inputs in the sheltered beach, which were not observed in the exposed one.