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- Anthropogenic particles ingestion by fish larvae in important nursery areas of Iberia (South Europe)Publication . Zeri, Giulia; Baptista, Vânia; Teodosio, Maria; Cruz, JoanaMicroplastics (MPs) are now widespread in the marine environment, and their levels are expected to rise as larger plastic debris continues to break down and new plastic waste enters the ocean. Microplastics ingestion has been documented in fish larvae, which are already particularly vulnerable to predation, environmental stressors, and starvation. This study examines for the first time MPs ingestion by wild fish larvae in Southern Iberia, focusing on two key nursery ecosystems of Portugal: the Ria Formosa coastal lagoon and the Guadiana River estuary. Fish larvae collected monthly from surface water, between April 2023 and March 2024, exhibited encounter rates (ER - Total number of ingested particles/ Total number of organisms analysed *100) of 12.99% in Ria Formosa and 11.54% in the Guadiana estuary. No significant differences were observed in ER among taxa and locations. The ingested particles ranged in size from 20 μm to 2 mm and were predominantly made of rayon, transparent and in the form of fibres. No correlation was found between the size of the larvae and that of the ingested particles. Although larval size had a positive effect on MP ingestion, this effect was not significant. There were no differences in polymer type ingestion among taxa. Our results underline the role of nursery areas as exposure spots and the underestimated pressure of the textile industry on marine ecosystems. Further research is needed to assess the potential consequences of this exposure for larval survival, recruitment success, and the health of adult fish populations.
- Comparative proteomic analysis of trioza erytreae nymphs developed on Citrus ×limon and Citrus ×sinensis host plantsPublication . Magalhães, Tomás Thormann Abranches de; Anjos Guerreiro, Liliana Isabel Tomé; Power, Deborah Mary; Pereira, José Alberto Cardoso; Duarte, Amilcar; Tomás Marques, NatáliaTrioza erytreae is a vector of Huanglongbing (HLB), a highly damaging citrus disease. Lemon plants (Citrus ×limon) are the preferred host for T. erytreae, although the underlying mechanisms behind this remain to be fully elucidated. A comparative proteomic analysis of T. erytreae nymphs in their fourth and fifth instars that were fed either lemon or sweet orange (SwO) was carried out to investigate the interaction with its hosts. A 24-hour sucrose feeding assay was conducted to understand proteomic responses to a nutrient-poor diet. Proteomic profiling using nanoscale liquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS) identified a total of 1,477 psyllid proteins with high confidence. Oviposition and nymphal development were also evaluated across citrus hosts, revealing higher numbers of nymphs developing on lemon than on SwO. Feeding on SwO enriched pathways related to “transmission across chemical synapses” and “metabolism of proteins”. Responses observed under a 24-hour sucrose-only diet enriched the biological processes “response to external stimulus”, “response to stress” and “cytoskeleton organization”. In contrast, these enrichments were absent on lemon host, suggesting that lemon provides a more favourable environment for psyllid development. In addition, nymphs developed on lemon exhibited enhanced energy metabolism and an increase in translation initiation factors. Overall, the results demonstrate that development strongly depends on host plant species, with SwO impairing optimal growth and lemon promoting successful nymphal development.
- A comparison of olfactory sensitivity in seawater- and freshwater-adapted bass, dicentrarchus iabraxPublication . Velez, Zélia; Hubbard, Peter; Guerreiro, Pedro MiguelFish rely heavily on olfaction for many aspects of their lives including foraging, defense, migration, and reproduction. Olfactory receptor neurons in the olfactory epithelium are in direct contact with the water, and are, therefore, exposed to changes in water chemistry. The European seabass, Dicentrarchus labrax, uses estuaries as feeding grounds and migrates between seawater and brackish water; but some can be found in 100% freshwater. However, little is known about how the olfactory system adjusts to waters of such different ionic composition and whether this affects its function and ability to discriminate between odorants. The aim of this study was, therefore, to compare olfactory sensitivity in seabass adapted to either seawater (SW) or freshwater (5 ppt; FW), to odorants conveyed at different salinities, using multi-unit recording from the olfactory nerve. In SW-adapted fish, olfactory sensitivity to amino acids (AA) was consistently higher when AA were presented in seawater (SW-AA) than when presented in freshwater (FW-AA), whereas in FW-adapted fish, olfactory sensitivity to FW-AA was either equal or slightly lower to SW-AA. SW-adapted fish responded to decreases in external [Ca2+] and to increases in external [Na+ ]. FWadapted fish responded to increases of both ions. In SW-adapted fish, Ca2+-free artificial seawater (ASW) completely inhibited olfactory responses to amino acids, whereas Na+ -free ASW had no effect. However, in FW-adapted fish, lack of either ion in the water had no effect. Taken together, these results suggest that, as a primarily marine species, the olfactory system of the seabass is more sensitive in seawater; however, it can still function in freshwater, albeit with reduced sensitivity. Furthermore, in seawater, the olfactory transduction process is likely mediated by influx of external Ca2+, but not Na+ . In FW-adapted fish, the transduction process relies on neither external Ca2+ nor Na+ , suggesting that the process of hyperosmoregulatory ability to adjust to life in ion-poor water. Further work is needed to clarify how changes in salinity affect olfactory sensitivity, and the mechanisms by which euryhaline species are able to adapt to such changes when moving between media of different ionic composition and variable pH.
- The copepod/artemia trade-off in the culture of long snouted seahorse hippocampus guttulatusPublication . Palma, Jorge; Hachero-Cruzado, Ismael; Correia, Miguel J.; Andrade, José Pedro AndradeThis study evaluated the effects of copepod use and copepod conditioning strategies on the growth and survival of long-snouted seahorse (Hippocampus guttulatus) juveniles from 1 to 60 days post-parturition (DPP). Four dietary treatments were tested: Artemia enriched for 24 h with Isochrysis galbana (control), daily collected copepods, copepods unfed for 48 h, and copepods enriched for 24 h with I. galbana. Juveniles fed copepod-based diets exhibited significantly higher growth and survival (p < 0.05) than those fed enriched Artemia. Mean standard length increased from 1.3 ± 0.1 cm at release to 5.9 ± 0.2, 7.5 ± 1.4, 7.1 ± 1.2, and 7.3 ± 1.1 cm at 60 DPP for the enriched Artemia, daily collected copepods, unfed copepods, and enriched copepods treatments, respectively. Wet weight increased from 0.002 ± 0.001 g to 0.44 ± 0.07, 0.81 ± 0.40, 0.68 ± 0.30, and 0.76 ± 0.40 g, while final survival reached 20%, 60%, 33.3%, and 56%, respectively. Compared with enriched Artemia, copepod-based diets markedly enhanced juvenile performance, supporting faster growth and promoting favorable behavioral traits that contributed to improved survival. These results demonstrate that copepods constitute a superior live feed for early juvenile H. guttulatus; however, copepod conditioning strategies directly influence their nutritional quality and, consequently, seahorse growth and survival. The use of copepods throughout the first 60 DPP is therefore not only feasible but strongly recommended for optimizing juvenile H. guttulatus rearing performance.
- A demographic model to forecast Dinophysis acuminata harmful algal bloomsPublication . Vieira, Vasco Manuel Nobre de Carvalho da Silva; Leal Rosa, Teresa; Sobrinho-Gonçalves, Luís; Mateus, Marcos Duarte; Mota, BernardoHarmful algal blooms (HABs) in marine environments have significant adverse effects on public health, aquaculture and recreational activities. Surges of certain phytoplanktonic toxin-producing microalgae (mostly dinoflagellates or diatoms species) can induce Amnesic, Diarrhetic or Paralytic Shellfish Poisoning (ASP, DSP and PSP). Among HAB species, the genus Dinophysis leads to DSP in human consumers; this being the most recurrent problem in the Iberian Peninsula with the biggest economic impact on clam production and harvesting. While complete elimination of HABs is not feasible, timely implementation of appropriate measures can prevent their negative consequences. This is critical for aquaculture. Research on D. acuminata (dominant Dinophysis species in the North Atlantic) has been focused on ecophysiology and population dynamics, although with few modelling attempts. Weekly monitoring along the Portuguese coast since 2006 has revealed that D. acuminata thrives under spring/summer photosynthetically active radiation (PAR) coupled with water temperatures below 20°C, which typically coincide with the local upwelling regime. In order to advance this knowledge numerically, we developed a demographic model linking D. acuminata growth rate to PAR and sea surface temperature (SST). The 13-year (1-Jan-2006 to 31-Dec-2018) time-series of observations was closely fit by model forecasts. However, the model demonstrated limitations in issuing timely warnings of harmful proliferation of D. acuminata, failing to do so in 50% of cases, and issuing incorrect warnings in 5% of the cases. Furthermore, improving the odds of emitting timely warnings always worsened the odds of emitting false warnings, and vice-versa. To simultaneously improve both aspects, the modelling results clearly indicated the need of implementing both census/ projection intervals smaller than 7 days and a laboratory detection limit below 20 cell/L. The time resolution of the census and of the model proved to be the most limiting factor that must be addressed in order to improve numerical forecasting of HABs.
- Detection and mitigation of paraphysomonas sp., a chrysophycean responsible for the collapse of industrial tisochrysis lutea culturesPublication . José, Mélissa; Paulino, Cristina; Schüler, Lisa; Pinto, Bruno; Carneiro, Mariana; Rodrigues, Alexandre M. C.; Pereira, Filipe; Pereira, Hugo; Varela, JoãoMicroalgae are increasingly recognized as a sustainable resource to address challenges associated with climate change and population growth, owing to their capacity to produce high-quality biomass for applications in feed, food, and cosmeceuticals. However, the expansion of microalgae-based industries remains constrained by harmful biological contaminants (HBCs), which can rapidly reduce productivity, often signalled by visible changes in culture appearance (e.g., cell aggregation and discoloration), and may ultimately lead to culture collapse and substantial economic losses. In this study, the grazer Paraphysomonas sp. (Chrysophyceae) was identified as the most likely cause of Tisochrysis lutea culture collapse in a large-scale production facility using high-throughput amplicon sequencing of the 18S rDNA gene. To enable early detection of this HBC during the scale-up process, a species-specific primer pair targeting the 18S rDNA gene was developed and optimized, allowing detection of Paraphysomonas sp. at relative abundances as low as 0.1%. The contaminant was first detected at the final stage of scale-up, in a tubular photobioreactor. To further characterize the impact of the grazer and support mitigation strategies, its feeding behaviour was examined. Laboratory-scale mitigation trials showed that treatment with germanium dioxide (GeO2) at 1 mg L⁻ 1 effectively delayed contaminant proliferation and prevented culture collapse without adversely affecting T. lutea growth. These findings highlight the value of integrating molecular monitoring with targeted mitigation strategies to improve early detection and management of HBCs in industrial microalgae production systems.
- Detection of paralytic shellfish toxins and tetrodotoxins in shellfish using a single-cell biosensor based on patch clamp technologyPublication . Reverté, Jaume; Turner, Andrew D.; Dhanji-Rapkova, Monika; Klijnstra, Mirjam D.; Gerssen, Arjen; Lage, Sandra; Tudó, Àngels; Diogène, Jorge; Sureda, Francesc X.; Campàs, MònicaParalytic shellfish toxins (PSTs) are a well-known group of potent neurotoxins that may accumulate in shellfish, posing a significant risk to food safety and public health. To protect consumers, shellfish production areas are subject to regulatory monitoring programs targeting PST contamination. However, tetrodotoxins (TTXs), another group of potent neurotoxins that may also accumulate in shellfish and co-occur with PSTs, are not currently included in regulations and routine monitoring schemes in most EU countries. This is of particular concern because PSTs and TTXs share the same biological target and mechanism of action and therefore pose a comparable neurotoxic risk. In this work, we present an automated patch clamp (APC) single-cell biosensing device as a toxicological bioanalytical solution addressing the need for tools capable of simultaneously detecting these two hazardous toxin groups. The biosensor was able to detect not only saxitoxin (STX) and TTX, but also their toxic analogues. The method achieved a limit of detection of 37 µg STX equivalents (equiv.) kg⁻¹, well below the current regulatory limit of 800 µg STX equiv. kg⁻¹. After the analysis of more than 70 samples exhibiting diverse toxin profiles, the results and correlations with reference methods demonstrate that APC single-cell biosensing provides a robust and integrative tool for the simultaneous monitoring of PSTs and TTXs.
- Dietary 1.3-1.6 yeast β-glucans enhance immune response and disease resilience in European seabass challenged with Tenacibaculum maritimumPublication . Orelhas Cabano, Miguel; Richard, Nadège; Schulthess, Julie; Pinto, Lourenço Ramos; Cunha, Francisco Pinto; Peixoto, Maria João; Aragão, Cláudia; Costas, BenjaminIntroduction: Nutritional strategies have emerged as promising tools to modulate immune responses in marine fish, particularly at mucosal surfaces involved in host-pathogen interactions. Dietary immunomodulators such as yeast-derived bglucans (BG) have gained attention for their capacity to enhance innate immune defenses, however their role in coordinating these mechanisms during bacterial infections remains incompletely understood. Methods: This study evaluated the effects of two dietary inclusion levels (0.06 and 0.12%) of purified yeast b-1,3/1,6-glucans on the immune responses of European seabass (Dicentrarchus labrax) following a bath challenge with Tenacibaculum maritimum specifically. After four weeks of feeding with experimental diets, fish were exposed to a sub-lethal infection, and immune parameters were accessed in the skin, intestinal mucosa and at systemic level. Results: Growth performance and feed efficiency were not affected by BG supplementation. At 24 h post-infection, fish fed with the 0.12% BG diet maintained circulating leukocyte counts and displayed increased plasma lysozyme activity, indicating enhanced early immune readiness. Moreover skin immune responses showed an early upregulation of pro-inflammatory and antimicrobial related genes, followed by increased expression of regulatory cytokines at 7 days post-infection, suggesting an efficient transition from immune activation to resolution. In contrast, intestinal immune responses remained largely unchanged, indicating a compartmentalized modulation focused on the primary site of infection. Conclusion: Overall, dietary BG supplementation exerted a dose dependent immunostimulatory effect in European seabass, with 0.12% BG eliciting the most significant chances in disease resilience
- Diversity of bioactive compounds in microalgae: key classes and functional applicationsPublication . Osathanunkul, Maslin; Thanaporn, Suebsuya; Karapetsi, Lefkothea; Nteve, Georgia Maria; Pratsinakis, Emmanouil; Stefanidou, Eleni; Lagiotis, Giorgos; Avramidou, Eleni; Zorxzobokou, Lydia; Tsintzou, Georgia; Athanasiou, Artemis; Mpelai, Sofia; Constandinidis, Constantinos; Pantiora, Panagiota; Merino, Marián; Mullor, José Luis; Dobrovic, Luka; Cerasino, Leonardo; Ogawa, Tomohisa; Tsaousi, Meropi; Rodrigues, Alexandre M. C.; Cardoso, Helena; Pires, Rita; Rodrigues Figueiredo, Daniel; Figueiredo, Daniel; Costa, Inês F.; Anjos, Catarina; Labrou, Nikolaos E.; Madesis, PanagiotisMicroalgae offer a sustainable and versatile source of bioactive compounds. Their rapid growth, efficient CO2 utilization, and adaptability make them a promising alternative to traditional production methods. Key compounds, such as proteins, polyunsaturated fatty acids (PUFAs), polyphenols, phytosterols, pigments, and mycosporine-like amino acids (MAAs), hold significant commercial value and are widely utilized in food, nutraceuticals, cosmetics, and pharmaceuticals, driving innovation across multiple industries. Their antiviral and enzyme-producing capabilities further enhance industrial and medical applications. Additionally, microalgae-based biostimulants and plant elicitor peptides (PEPs) contribute to sustainable agriculture by enhancing plant growth and resilience to environmental stressors. The GRAS status of several species facilitates market integration, but challenges in scaling and cost reduction remain. Advances in biotechnology and metabolic engineering will optimize production, driving growth in the global microalgae industry. With increasing consumer demand for natural, eco-friendly products, microalgae will play a vital role in health, food security, and environmental sustainability.
- Do toxic epiphytic microalgae compromise the consumption of edible macroalgae?Publication . Chainho, Tomás; Cereja, Rui; Barbosa, Miguel; Xavier, Maria João; Pereira, Alícia; Oliveira, Inês; Caria Mendes, Madalena; Marques, António; Reis Costa, PedroThe growing global demand for farmed macroalgae highlights the need to better understand potential contaminant loads, including toxins from harmful algal blooms, and their implications to human health. In this study, the green macroalga Ulva rigida was co-cultivated with the epiphytic dinoflagellate Prorocentrum lima to determine whether toxins produced by the toxic dinoflagellate accumulate in the macroalgae and assess the efficacy of post-harvest processing techniques to reduce or eliminate the risk of toxins contamination. Ulva rigida (60 g wet weight) was maintained under controlled laboratory conditions in sterile F/2 medium and in co-culture with P. lima. Macroalgae were divided into two treatments: a) no processing; b) processing. Samples were analysed by LC-MSMS to detect okadaic acid (OA) and dinophysistoxin-1 (DTX1). High toxins levels were detected after 7 days of exposure to P. lima. Contrastingly, the post-harvesting process of washing and scrubbing was efficient in reducing toxins loads, indicating that lipophilic toxins were surface bound and can be easily eliminated using efficient post-harvest processes. The results indicate that epiphytic toxic microalgae may jeopardize the consumption of macroalgae, particularly if appropriate post-harvest processes are not applied to ensure the safety of farmed macroalgae for consumers.