Sapientia
Repositório Científico da UAlg
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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, Joana
Microplastics (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.
MARS lander: georeferencing landing and pop points of untethered ocean monitoring systems using fundamental physics
Publication . Radeta, Marko; Behboodi, Zahra; Zekovic, Vladimir; Alves, Décio; Pestana, David; Nunes, Daniel; Freitas, Margarida; Gupta, Ankit; Pestana, João; Vieira, Dinarte; Almeida, Sílvia; Dias, Morgado; Clode, João Canning; Caldeira, Rui; Relvas, Paulo; Vasiljevic, Antonio
Subsurface observations are crucial for understanding the ocean's role in Earth's climate and for refining climate models. However, existing aquatic monitoring systems that allow such insights remain complex and costly due to their high demands for deployment, sampling, and recapture. Since low-cost, easy-to-deploy deep-sea landers are scarce, and with the aim of facilitating more subsurface observations, this study provides a simple method for georeferencing small-sized untethered landers. Their underwater trajectories are modelled with fundamental physics, dead reckoning, lander geometry, and numerical simulations. Using free fall, upthrust, and ocean current dynamics, the proposed approach estimates their underwater trajectories, including landing (at the seabed) and pop (at the sea surface) points. The method relies on the lander's physical characteristics, including its vertical and horizontal cross-sectional areas, to calculate the drag force coefficients used to determine its trajectories during descent and ascent through the water column. Ocean currents' magnitudes are modelled using Ekman's exponential decay down to 90 m of the water column, while the depths until 900 m are modelled from prior ADCP surveys by varying ocean current headings with depth between − 20 and 20◦. Surface ocean and wind current headings are modelled with open datasets from satellite telemetry. Lander's velocity, displacement, and dive time to the landing and pop points, including the total radial excursion and uncertainty in heading, are analytically derived, numerically calculated, and empirically assessed a-posteriori until 90 m, yielding a ~38 m radial excursion (40% error) against the obtained GNSS coordinates in field deployment, and 33◦ in heading uncertainty during a 138-s excursion. Additional random walk simulations are shown for full ocean depth obtaining radial excursion of 1038 m with 278 min total dive time. This approach is generalizable to any subsurface aquatic monitoring systems targeting deployments with diverse payloads from smaller sea vessels, not requiring cranes, radio, GNSS, or acoustic telemetry. Since it accounts for key nature factors, our method provides special benefits in planning and optimizing deployments. Additional discussion focuses on the method's practicality for full ocean depth deployments.
SAMMBA is a high-throughput pipeline for isolating and phenotyping macroalgal strains
Publication . Alves-Lima, Cicero; de Matos Barreto, Luís António; Mónico, Carina; Gouvêa, Lidiane; Félix de Azeredo Pinto e Melo, Francisca; Varga, Brigitta; Filipe, Joana; Camacho, Rita; Lymperaki, Myrsini; Alberto, Filipe; Rörig, Leonardo R.; Engelen, Aschwin; Serrao, Ester A.; Pearson, Gareth Anthony; Martins, Neusa
Despite successful preservation efforts, macroalgal diversity remains under-represented in global biobanks. A major limitation is the extreme morphological diversity of seaweed thalli, which hinders standardized isolation and phenotyping and often requires taxon-specific protocols. Here we present SAMMBA (Seaweed Automatable Microplate Microscopy for Breeding Approaches), an end-to-end pipeline for the high-throughput isolation, phenotyping and storage of macroalgal propagules in 384-well plates. By optimizing live-cell manipulation for chlorophyll autofluorescence (CAF) imaging and segmentation, multiple unialgal propagules can be isolated by dilution-based workflows. In a single plate, we obtained 68 singlet gametophyte fragments of Laminaria ochroleuca (17.7%) and 60 meiospores of Phyllariopsis purpurascens (31.25%). We demonstrated taxonomic and morphological versatility by isolating 60 unialgal cultures from three distinct Rhodophyta morphotypes (filamentous, crustose and foliose) and 10 strains of Ulva sp., also in a single plate. Furthermore, CAF-based area increase over 30 days enabled high-precision estimates of specific growth rates, yielding 0.130 ± 0.006 and 0.117 ± 0.01 day− 1 for male and female L. ochroleuca gametophytes, respectively (n = 768; p = 1.27e− 53). This precision substantially increases experimental reproducibility and statistical power compared to conventional methods, supporting high-throughput recovery of unialgal strains without motorized platforms, while remaining fully compatible with automation. SAMMBA expands operational capacity for strain discovery and phenotyping, providing a scalable foundation for phenomics, domestication workflows, and standardized macroalgal biobanking. We outline how the platform can benefit multiple areas of phycological research and facilitate the development of improved strains that can support aquaculture and restoration efforts.
Deciphering the diet of the iberian iynx: insights from taphonomic analysis of pleistocene coprolites
Publication . Rufà, Anna; Sanz, Montserrat; Daura, Joan
Pleistocene deposits often result from multiple and overlapping contributions. Carnivores play a significant role as bone accumulators in archaeological sites, but identifying the specific agent responsible for a particular accumulation can be challenging. Referential studies provide valuable insights into bone accumulation patterns, but they are based on modern collections and often fail to account for taphonomic biases associated with site formation processes. Here, we present, for the first time, a taphonomic study focused on fossilised Pleistocene Iberian lynx coprolites within the European context. The assemblage, dated to ca. 33 ky B.P., was recovered from layer III of Cova del Gegant, a site identified as a lynx den likely used for rearing cubs. This study is based on previous research at the site and analyses bone remains consumed by the Iberian lynx (Lynx pardinus), recovered from coprolites, to investigate their role in archaeological contexts. The findings are consistent with other lynx accumulations documented in literature, particularly regarding leporid remains. The anatomical proportions in this assemblage are more balanced than other types of accumulations, with a higher representation of cranial elements. Digestive damage is predominant, affecting most bones, especially at moderate and strong degrees. These results enhance our understanding of archaeological accumulation processes and highlight the role of lynxes as bone accumulators. The archaeological evidence from the site indicates that the Iberian lynx inhabited environments and climates that differ significantly from those currently observed. However, the present study suggests that its diet remained relatively consistent with that of contemporary Iberian populations.
Improving monitoring, control and surveillance efforts through vessel tracking and fishery dependent data
Publication . Sales Henriques, Nuno; Russo, Tommaso; Erzini, Karim; Gonçalves, Jorge Manuel Santos
Fisheries are amongst the most extractive and damaging activities impacting the marine environment. To control and promote the sustainability of these activities, different laws and regulations were established. Yet, Illegal, Unregulated and Unreported (IUU) fishing activities are still present to these days and are one of the most threatening problems affecting marine life. To improve the effectiveness of fishing control and surveillance efforts, risk assessment approaches have been proposed to detect risk units with higher probability of illegal actions, such as vessels, seasons or regions, to which control efforts should be given priority. Vessel tracking and fishery dependent data have already proved their potential for gathering important information regarding different aspects of fishing activities, such as species distributions or the estimation of fishing effort. Yet, their usefulness for improving monitoring, control and surveillance efforts has not been fully exploited. Here, we investigate how these two types of data can provide important intelligence, within a risk assessment approach, to identify risk units that have higher probability of failing with landing requirements and how such information can be used to improve fisheries’ monitor, control and surveillance efforts. Our approach is able to identify fishing vessels with higher tendency for not reporting their catches. We saw that a small fraction of fishing vessels are responsible for the majority of unreported landings and that unreported landing events tend to less frequent during the Summer. We also noticed that price variation of sold catches correlates with unreported landing events, which might indicate that it is one of the drivers affecting the seasonality of unreported landing events. Such information is crucial when planning control and enforcement actions, which should focus on those with a higher tendency to act incompliantly and during the periods when this sort of behaviour is more frequent. By following this approach, such effort become more cost effective, which will strengthen the governance of the marine realm.