Discerning natural and anthropogenic organic matter inputs to salt marsh sediments of Ria Formosa lagoon (South Portugal)

Sedimentary organic matter (OM) origin and molecular composition provide useful information to understand carbon cycling in coastal wetlands. Core sediments from threors' Contributionse transects along Ria Formosa lagoon intertidal zone were analysed using analytical pyrolysis (Py-GC/MS) to determine composition, distribution and origin of sedimentary OM. The distribution of alkyl compounds (alkanes, alkanoic acids and alkan-2-ones), polycyclic aromatic hydrocarbons (PAHs), lignin-derived methoxyphenols, linear alkylbenzenes (LABs), steranes and hopanes indicated OM inputs to the intertidal environment from natural-autochthonous and allochthonous-as well as anthropogenic. Several n-alkane geochemical indices used to assess the distribution of main OM sources (terrestrial and marine) in the sediments indicate that algal and aquatic macrophyte derived OM inputs dominated over terrigenous plant sources. The lignin-derived methoxyphenol assemblage, dominated by vinylguaiacol and vinylsyringol derivatives in all sediments, points to large OM contribution from higher plants. The spatial distributions of PAHs (polyaromatic hydrocarbons) showed that most pollution sources were mixed sources including both pyrogenic and petrogenic. Low carbon preference indexes (CPI > 1) for n-alkanes, the presence of UCM (unresolved complex mixture) and the distribution of hopanes (C-29-C-36) and steranes (C-27-C-29) suggested localized petroleum-derived hydrocarbon inputs to the core sediments. Series of LABs were found in most sediment samples also pointing to domestic sewage anthropogenic contributions to the sediment OM.EU Erasmus Mundus Joint Doctorate fellowship (FUECA, University of Cadiz, Spain)EUEuropean Commission [FP7-ENV-2011, 282845, FP7-534 ENV-2012, 308392]MINECO project INTERCARBON [CGL2016-78937-R]info:eu-repo/semantics/publishedVersio

Learning from humpback whales for improving the energy capturing performance of tidal turbine blades

This paper summarizes a project on the potential of further improving the performance of horizontal axis tidal turbines via the application of leading-edge tubercles to the turbine blades inspired by humpback whales. Within this framework, a wide variety of experimental investigations, supported by numerical studies, have been conducted. The study first focused on the design and optimisation of the leading-edge tubercles for a specific tidal turbine blade section by using numerical methods to propose an “optimum” design for the blade section. This optimum design was then applied onto a representative tidal turbine blade. This representative 3D blade demonstrated significant benefits, especially after stall. The experimental measurements were further validated and complimented by numerical simulations using commercial CFD software for the detailed flow analysis. Following that, three tidal turbine models with varying leading-edge profiles were manufactured and a model test campaign was conducted in the cavitation tunnel to evaluate their efficiency, cavitation, underwater noise, and detailed flow characteristics. Based on these experimental investigations it was confirmed that the leading-edge tubercles can improve the hydrodynamic performance in the low Tip Speed Ratio (TSR) region without lowering the maximum power coefficient; constrain the cavitation development to within the troughs between the tubercles; and, hence, mitigate the underwater noise levels