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- Monitoring invasive macroalgae in southern Portugal: drivers and citizen science contributionPublication . Jiménez, Javier; Simes, Dina; Abecasis, Ana Rita Costa; Relvas, Paulo; Garel, Erwan; Martins, Paula Ventura; Santos, RuiUnder certain environmental and oceanographic conditions, macroalgae can overgrow and accumulate in massive quantities on beaches, causing serious ecological and economic impacts. To address this problem, a citizen science monitoring platform was created to determine the spatial and temporal distribution of macroalgae accumulations along the beaches of Algarve in southern Portugal, with the aim to assess the extent of beach-cast events and their relationship with abiotic factors. A Redundancy Analysis (RDA) and a permutational analysis of variance (PERMANOVA) were carried out to explore the relationship between macroalgae accumulation level and the abiotic variables: sea surface temperature, wind speed, wind direction, currents, maximum sea level, significant wave height, salinity, nitrate, ammonium, phosphate, precipitation and radiation. The citizen science campaign showed great participation, resulting in 404 submissions between July 2021 and September 2023. The campaign revealed that three species of macroalgae accumulated on the beaches of Algarve, Ulva sp. (with the presence of Ectocarpales and Dyctiotales) along the sandy eastern coast, and the invasive species Asparagopsis armata and Rugulopteryx okamurae in the rocky central and western beaches, respectively. The accumulations of R. okamurae increased from 2021 to 2023, were registered throughout the year and were more abundant than those of Ulva sp. and A. armata, which were only observed in spring and summer. The highest levels of R. okamurae beach-cast depositions were related to strong wave conditions, and high sea surface temperature and salinity. The accumulation of Ulva sp. was related to high sea surface temperature and salinity whereas A. armata was also correlated with winds parallel to the shore (NW-W). PERMANOVA analysis revealed that sea surface temperature and wave conditions had a significant effect on the overall abundance of macroalgae beach-cast accumulations. Overall, our citizen science campaign effectively involved the public, leading to the collection of important data on monitoring macroalgae accumulations. Through these findings, we were able to pinpoint the environmental, atmospheric, and hydrodynamic factors that contribute to their development, movement, and buildup along the Algarve coastlines.
- The impact of egg thermal regimes on the response to food deprivation and refeeding in juvenile European sea bass (Dicentrarchus labrax)Publication . Mateus, Ana; Costa, Rita; Jiménez, Javier; Sadoul, Bastien; Bégout, Marie Laure; Cousin, Xavier; Canario, Adelino; Power, DeborahFish are ectotherms and this means they are highly vulnerable to changes in ambient temperature, particularly during early developmental stages when temperature can induce persistent effects on phenotypic traits. In this study, the effect of egg incubation temperature on the response of juvenile European sea bass (Dicentrarchus labrax) to food deprivation and recovery after refeeding was assessed. Eggs were incubated at 11, 13.5 and 16 & DEG;C until hatching and then were reared at a common temperature until 9 months when fish were deprived of food for one week. The recovery from food deprivation was evaluated at 10 h and 2 days post-refeeding. Food deprivation in fish from eggs incubated at the highest temperature (16 & DEG;C) compared to 11 and 13.5 & DEG;C exhibited the most morphological and metabolic changes in the liver and foregut. Liver metabolism was changed as revealed by the significant reduction in lipid area and the increased number of hepatocyte nuclei. Foregut atrophy was coupled to a significant up-regulation of transcripts associated with gluconeogenesis (pck1) and peptide absorption (pept1). A modified metabolic response to the fast-refeed regime was revealed by the significantly decreased levels of plasma lactate, which may result from up-regulation of transcripts of the thyroid axis, deiodinase 2 (dio2) in the foregut. Fish incubated as eggs at a lower temperature (11 & DEG;C) exhibited less changes following the fast-refeed regime. Food deprivation did not significantly modify the morphology of the foregut and the liver parenchyma recovered sooner in fish from the 11 & DEG;C egg thermal regime compared to fish from the other thermal regimes following refeeding. The latter group of fish had a temporary stimulation of the GH-IGF axis with significant up-regulation of liver insulin-like growth factor I and II (igf-1 and igf-2) after fasting. The liver parenchyma of fish from the 13.5 & DEG;C egg thermal regime (the standard temperature of the hatchery stage) did not recover by the end of the experiment and transcripts of catalase (cat), encoding an antioxidant enzyme, were significantly downregulated compared to fish from the other egg thermal regimes. Our results suggest that thermal imprinting at the egg stage in European sea bass modified the juvenile metabolic response to food deprivation and the recovery response when feeding was resumed.
- Functional traits of ecosystem engineers as predictors of associated faunaPublication . Jiménez Herrero, Javier; Desiderato, Andrea; Vieira, Pedro Emanuel; Tavares, Ana Mafalda; Queiroga, Henrique; Santos, RuiThe ongoing combination of global warming and increased anthropogenic pressure is causing latitudinal shifts in marine species, potentially impacting community composition, local richness, and marine trophic webs. This study investigates the factors influencing the distribution and diversity of intertidal seaweed and associated peracarid communities, including their functional traits, and explores various facets of beta diversity (taxonomic and functional). We hypothesize that: 1) abiotic factors such as temperature and anthropogenic pressure significantly influence seaweed distribution and diversity shifts, and 2) changes in seaweed functional diversity have an impact on the diversity and functioning of its associated peracarid communities. The sampling was conducted along a wide latitudinal gradient in the NE Atlantic (27(degrees)N - 65(degrees)N), encompassing three distinct ecoregions: Northern European coasts, the Iberian Peninsula, and Macaronesia. The identified seaweed and peracarid species were classified functionally, and taxonomic and functional diversity were analysed on a large geographic scale. The northern region exhibited large brown canopy seaweeds and epibiotic isopods, while Macaronesia featured small red, highly branched, and calcareous crust seaweeds with burrower and tubebuilding tanaids. The Iberian Peninsula acted as a transitional zone, showcasing a mix of green, red, and brown seaweeds, along with Amphipoda peracarids found across all ecoregions. Our findings underscore the impact of geographic distance on total beta diversity, revealing distinct seaweed and peracarid communities across spatial gradients. Environmental variables, particularly pH and maximum sea surface temperature, emerged as significant factors influencing beta diversity patterns of seaweeds, indicating the potential impact of acidification and heat waves on community composition. In addition, seaweed functional traits were shown to be significant in shaping the diversity and abundance of associated peracarid assemblages, impacting both taxonomic and functional beta diversity. These findings provide crucial insights into the factors influencing the biogeography and biodiversity dynamics of intertidal seaweeds and associated peracarids, offering essential implications for conservation and management strategies amid ongoing environmental changes.