Browsing by Author "Carvalho, Liliana"
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- Assessing land–ocean connectivity via submarine groundwater discharge (SGD) in the Ria Formosa Lagoon (Portugal): combining radon measurements and stable isotope hydrologyPublication . Rocha, Carlos; Veiga-Pires, C.; Scholten, Jan; Knoeller, Kay; Gröcke, Darren R.; Carvalho, Liliana; Aníbal, J.; Wilson, JeanNatural radioactive tracer-based assessments of basin-scale submarine groundwater discharge (SGD) are well developed. However, SGD takes place in different modes and the flow and discharge mechanisms involved occur over a wide range of spatial and temporal scales. Quantifying SGD while discriminating its source functions therefore remains a major challenge. However, correctly identifying both the fluid source and composition is critical. When multiple sources of the tracer of interest are present, failure to adequately discriminate between them leads to inaccurate attribution and the resulting uncertainties will affect the reliability of SGD solute loading estimates. This lack of reliability then extends to the closure of local biogeochemical budgets, confusing measures aiming to mitigate pollution. Here, we report a multi-tracer study to identify the sources of SGD, distinguish its component parts and elucidate the mechanisms of their dispersion throughout the Ria Formosa – a seasonally hypersaline lagoon in Portugal. We combine radon budgets that determine the total SGD (meteoric + recirculated seawater) in the system with stable isotopes in water (δ2H, δ18O), to specifically identify SGD source functions and characterize active hydrological pathways in the catchment. Using this approach, SGD in the Ria Formosa could be separated into two modes, a net meteoric water input and another involving no net water transfer, i.e., originating in lagoon water re-circulated through permeable sediments. The former SGD mode is present occasionally on a multi-annual timescale, while the latter is a dominant feature of the system. In the absence of meteoric SGD inputs, seawater recirculation through beach sediments occurs at a rate of ∼ 1.4 × 106 m3 day−1. This implies that the entire tidal-averaged volume of the lagoon is filtered through local sandy sediments within 100 days ( ∼ 3.5 times a year), driving an estimated nitrogen (N) load of ∼ 350 Ton N yr−1 into the system as NO3−. Land-borne SGD could add a further ∼ 61 Ton N yr−1 to the lagoon. The former source is autochthonous, continuous and responsible for a large fraction (59 %) of the estimated total N inputs into the system via non-point sources, while the latter is an occasional allochthonous source capable of driving new production in the system.
- Climate change and tourism: scholars’ reflections on transformative researchPublication . Farsari, Ioanna; Bakker, Martine; Carvalho, LilianaClimate change has become a key topic of attention within the tourism industry and among tourism scholars over the last 20 years however, research has largely focused around the industry’s and entrepreneurs’ perceptions (Tervo-Kankare, 2019); impacts and adaptation measures in destina tions (Becken et al., 2020; Demiroglu et al., 2019; Scott et al., 2019); or tourists’ perceptions and travel behaviour (Becken et al., 2021). Although the need for transformative changes in societies and in the tourism system has drawn research interest (Bellato et al., 2022; Bertella, 2022; Pritchard et al., 2011) there is little discussion around the transformative nature of tourism research regarding climate change. Transformative approaches invite the researcher to reflect and critically examine their role in maintaining unsustainability or bringing change (Mertens, 2021). Epistemologically, they acknowledge the subjective character of research and point to the direction of communication of researcher’s role and values. While transformative approaches acknowledge the importance of reflexivity, researchers’ identities, diverse interests and power, they enable the integration of conventional and disruptive methodologies. Collaborative methods aiming to bridge the theory practice gap, together with reflexivity, have this transformation potential through co-creation and caring (Liburd et al., 2022). With this research note, we want to draw attention to those aspects and invite discussion around climate change and tourism research and reflexivity over our scholarly role. To the knowledge of the authors, there is very little documentation and discussion on how we, tourism scholars, present, discuss and reflect on our research and our role as scholars, and more specifically around transformative climate change research