Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

摘要: Abstract Growing human population adds to the natural nitrogen loads coastal waters. Both anthropogenic and is readily incorporated in new biomass, these different sources may be traced by measurement of ratio stable isotopes (δ 15 N). In this study δ N was determined two species macroalgae ( Ascophyllum nodosum Fucus vesiculosus ), nitrate ammonium determine relative importance versus along coast NW Spain. algal showed similar isotopic enrichment for a given site, but not related either inorganic concentrations or water samples. The latter suggests that inputs are variable do always leave an trace macroalgae. However, significant linear decrease macroalgal consistent with differential effect upwelling. Besides geographic variability, influence evidenced higher from rias estuaries compared those open areas more than 15 × 10 3 inhabitants watershed. These results indicate that, contrast other studies, simply size depends on factors as upwelling efficiency local waste treatment systems.