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The effect of riparian forest on landscape connectivity for the EPT community across European regions

Publication . Peredo Arce, Andrés; Kail, Jochem; Tasser, Erich; Feio, Maria João; Palt, Martin; Schletterer, Martin

Ephemeroptera, Plecoptera and Trichop- tera are three orders of freshwater macroinvertebrates with a short terrestrial adult life-stage that they use to disperse by flying upstream. This aerial dispersal can be assisted by native riparian forest, but regional variation has not yet been empirically tested. In this study we compared the EPT community of 153 sampling sites located in freshwater streams in four European regions (Central Plains, Central Highlands, Alps, Iberia). In each site, we assessed the EPT com- munity dispersal ability using the Species Flying Pro- pensity index. We also calculated the native decidu- ous forest cover in the riparian buffer and several environmental stressors such as saprobic pollution or catchment anthropization. Finally, we tested which of these parameters have a significant effect on the EPT community. In the Central Highlands and in Iberia, the share of weak dispersers increased with native deciduous forest cover, indicating a positive effect on dispersal of EPTs. In the Central Plains and the Alps, no such effect was found. We conclude that the effect of native deciduous forest depends on regional land- scape characteristics and the regional species pool, but considering the dispersal of the regional EPT communities is needed to create effective river man- agement policies.

2023Journal article

Open access

Freshwater fish community assessment using eDNA metabarcoding vs. capture-based methods: Differences in efficiency and resolution coupled to habitat and ecology

Publication . Curto, Manuel; Batista, Sofia; Santos, Carlos D.; Ribeiro, Filipe; Nogueira, Sofia; Ribeiro, Diogo; Prindle, Benjamin; Licari, Daniel; Riccioni, Giulia; Dias, Diogo; Pina-Martins, Francisco; Jentoft, Sissel; Veríssimo, Ana; Alves, Maria Judite; Gante, Hugo F.

Environmental DNA (eDNA) metabarcoding has revolutionized ecological and environmental research by describing communities without relying on direct observations, making it a powerful, non-invasive, and cost-effective tool in biodiversity monitoring. However, the adoption of eDNA as a standard protocol in long-term monitoring programs, which have traditionally relied on capture-based methods, presents challenges in terms of data comparability. Here, we compared freshwater fish communities assessed through eDNA metabarcoding and electrofishing, across 35 sampling sites in the lower Tagus River basin, Portugal. For the majority of species or species-groups analysed individually (13 out of 17), a significant correspondence was observed between electrofishing and eDNA metabarcoding detections. A weaker correspondence was found between the number of specimens captured by electrofishing with the number of eDNA metabarcoding reads, with seven out of 13 taxa showing significant relationships. Species richness estimates based on the two methods were very similar at the basin level. The methods yielded significantly different species compositions, although these differences were driven by samples collected in the Tagus main channel, which is wider and has higher flow rates than tributaries. Benthic and shoreline fish communities showed similar species composition in the two methods, but this was not the case for pelagic communities, probably due to the higher water turnover of the pelagic zone and electrofishing inefficiency. Our results highlight the high potential of eDNA metabarcoding as a complementary method to electrofishing for freshwater fish monitoring, though further validation is needed to assess biases related to site-specific hydrological conditions and the ecology of the target species.

2025-06Journal article

Embargoed access

Sharks in a changing ocean : a multiscale assessment of anthropogenic pressures on key marine predators

Publication . Santos, Catarina; Rosa, Rui Afonso Bairrão da; Santos, Catarina Frazão da Fonseca Ribeiro dos; Miranda, Pedro Michael Cavaleiro de

With over a third of their species threatened with extinction, sharks and their relatives have been struggling to cope with the challenges brought upon them by the Anthropocene. While overexploitation has been driving the worldwide decline of this group, the rapidly escalating environmental changes triggered by anthropogenic activities are posed to further test their resilience. By integrating information obtained through distinct approaches, the present dissertation addresses a series of research questions regarding the effects of anthropogenic threats — namely climate change — over sharks, aiming to provide a stepping-stone towards a more holistic understanding of how this group may fare in the oceans of tomorrow. Specifically, through a systematic overview of the scientific landscape, chapter 2 gauges how trends in shark research have evolved over time and are distributed across both spatial and biological dimensions, revealing a clear shift in the motivations driving research over time, along with a marked spatial bias. Additionally, it showcases how, despite the recent increase in the number of studies, climate change remains one of the least studied threats. In this context, chapter 3 banks on decades of literature across the marine tree of life to, through a sequence of meta-analyses, provide critical insights into the effects of warming, acidification, and oxygen loss — highlighting the nefarious impacts of the latter. Meanwhile, chapter 4 uses a similar approach to contrast the effects of warming and acidification over elasmobranchs, considering distinct biological responses and functional attributes. It showcases the clear and pervasive effects of warming and identifies the specific gaps in experimental climate change research featuring sharks, underscoring the paucity of research on oxygen loss. Chapter 5 proposes a framework to evaluate the climate associated risk at the species-level based on species attributes and ecosystem-dependencies, assessing all extant sharks at the global scale. It emphasizes the imminence of the threat imposed by climate change over this group, with many species likely to be impacted over the short-term, and the considerable long-term differences in the scale of impacts caused by distinct scenarios, along with the nature and scale of functional implications. Finally, Chapter 6 uses a correlative approach to project how different emission scenarios may impact the habitat suitability and, consequently, the distribution patterns of sphyrnid sharks, a unique and particularly threatened group of elasmobranchs. In this context, the present dissertation highlights how the timely consideration of climate change is key to the long-term success of management plans, hopefully contributing to future conservation and research endeavors targeting this key group of marine predators.

2023-12Doctoral thesis

Embargoed access

Production of human milk fat substitutes by lipase-catalyzed acidolysis: immobilization, synthesis, molecular docking and optimization studies

Publication . Soares, Cleide M. F.; Barbosa, Milson S.; Santos, Samuel B.; Mattedi, Silvana; Lima, Álvaro S.; Pereira, Matheus M.; Tecelão, Carla; Ferreira-Dias, Suzana

Human milk fat (HMF) triacylglycerols (TAGs) mainly contain palmitic acid esterified at the sn-2 position while oleic and other unsaturated fatty acids are located at positions sn-1,3. This study aimed at the production of HMF substitutes (HMFS) by lipase-catalyzed acidolysis of tripalmitin with oleic acid, in a solvent-free medium. Burkholderia cepacia lipase (BCL) was immobilized in silica (prepared with protic or aprotic ionic liquids) by covalent binding or encapsulation and used as biocatalyst. The supports and immobilized biocatalysts were characterized by FTIR, TGA, and SEM. Molecular docking analysis showed that BCL preferentially attacks oleic acid rather than tripalmitin, due to the lower free energy of hydrophobic binding with this acid (􀀀6.5 kcal mol􀀀1) than with tripalmitin (5.4 kcal mol􀀀1). Therefore, the tripalmitin attack by BCL and subsequent HMFS production only occurs after the binding to most of the oleic acid molecules. The highest acidolysis activity was obtained with BCL immobilized by covalent binding in prepared silica with aprotic ionic liquid. A central composite rotatable design, as a function of temperature (58–72 C) and oleic acid/tripalmitin molar ratio (MR = 2:1–6.8:1), was performed for acidolysis optimization. Under optimized conditions (58 C and MR = 4:1 or 60 C and MR = 2:1), the oleic acid incorporation of 28 mol.% was achieved after 48 h.

2023-05Journal article

Open access

Nanoplastics activate a TLR4/p38-mediated pro-inflammatory response in human intestinal and mouse microglia cells

Publication . Antunes, Joana; Sobral, Paula; Martins, Marta; Branco, Vasco

The crescent presence of nanoplastics in the environment raises concerns regarding their potential impact on health. This study exposed human colon adenocarcinoma cells (HT29) and microglia cells (N9) to nanoplastics (25 nm, 50 nm, and 100 nm Polystyrene) to investigate their inflammatory responses, which are vital for body's defence. Although cytotoxicity remained generally low, HT29 cells exhibited a notable upregulation of p50 and p38 expression, concomitant with elevated TLR4 expression, in contrast with N9 cells that showed a less pronounced upregulation of these proteins. Additionally, nanoplastic exposure increased IL-1ß levels, partially attenuated by pre-exposure to TLR4 or p38 inhibitors. Intriguingly, N9 cells exposed to nanoplastics exhibited substantial increases in iNOS mRNA. This effect was entirely prevented by pre-exposure to TLR4 or p38 inhibitors, while TNF-α mRNA levels remained relatively stable. These findings underscore the potential of nanoplastics to activate inflammatory pathways, with response kinetics varying depending on the cell type.

2023-10Journal article

Open access