Analysis of Zebrafish contamination with heavy metals using a FF-XRF imaging system based on a MPGD

Funding Information: F.D. Leite is grateful for the grant BII/UI96/9175/2020, R.G. Oliveira is grateful for the grant SFRH/BI/10638/2020, and P.M.S. Carvalho is grateful to FCT for the PhD grant PD/BD/128324/2017. Funding Information: The costs resulting from the FCT (Fundação para a Ciência e a Tecnologia, I.P–Portuguese Foundation for Science and Technology) hiring L.F.N.D. Carramate were funded by national funds (OE) in the scope of the framework contract CEECIND/01369/2017, and S. Pessanha in the scope of the framework contract CEECIND/00278/2018. Funding Information: This work was partially supported by projects PTDC/FIS-AQM/32536/2017, CERN/FIS-INS/0026/2019 and STRONG-2020–824093 through FCT and H2020 programs. It was also developed within the scope of the i3N (UIDB/50025/2020 & UIDP/50025/2020) and CESAM (UIDP/50017/2020 & UIDB/50017/2020 & LA/P/0094/2020), financed by national funds through the FCT/MEC COMPETE , FEDER and POCI programs. Publisher Copyright: © 2022 The AuthorsHeavy metals have been extensively used by humans and are still present in many aspects of modern-day life. Such elements tend to accumulate, degrading the quality of air, soil, and water, negatively affecting the living organisms. As such, it is of paramount importance to understand the environmental risks of heavy metals, including their bioaccumulation capacity in organisms, since they are associated with several harmful health effects, such as neurological damages. The Zebrafish (Danio rerio) has been shown to be an excellent animal model to understand physiological responses in mammals and consequently to perform toxicological studies due to characteristics such as the high genetic and physiological similarity with humans. In this work, a Full-Field Energy Dispersive X-ray Fluorescence (FF-XRF) imaging system, based on the 2D-THCOBRA micropattern gas detector, was used to monitor heavy metal accumulation in Zebrafish during a water borne exposure bioassay. The distributions of Mn, Se, and Pb in Zebrafish, exposed to different concentrations of the heavy metal compounds during different time intervals, were mapped. The results show a preferential accumulation of Mn, Se, and Pb in the Zebrafish's visceral region and highlight the suitability of the FF-XRF imaging system for quick screening of metal accumulation in fish bioassays.publishersversionpublishe

Cross-referencing unidentified fish sound data sets to unravel sound sources: a case study from the Temperate Northern Atlantic

There is growing evidence that studying aquatic acoustic communities can provide ecologically relevant information. Understanding these communities may offer unique insights into species behaviour and ecology, while consolidating passive acoustic monitoring as a tool for mapping the presence of target species or estimating changes in aquatic biodiversity. Fish can be significant soundscape contributors, but most soniferous fish species are yet to be identified. Here, we crossed information of three key fish acoustic communities in the Lusitanian Province of the Temperate Northern Atlantic (the Madeira archipelago, the Azores archipelago and Arrábida in mainland Portugal) to unveil potential sources of unidentified fish sounds. We found that the three communities shared various sound types and we were able to narrow down the list of possible fish sound sources. Several sound types were suggested to be produced by species of the Pomacentridae, Scorpaenidae and Serranidae families. We also observed that the sound type /kwa/, associated with Scorpaena spp., exhibited more variations in the geographic area where more species of this genus are known to be present. This study showcases that, as databases of unidentified fish sounds continue to grow, future comparisons of multiple acoustic communities may provide insights into unknown fish sound sources and sound types

Nycthemeral and Monthly Occupation of the Fish Assemblage on a Sheltered Beach of Baía Norte, Florianópolis, Santa Catarina State, Brazil

Interpreting fish community records is challenging for several reasons, including the lack of past ichthyofauna data, the cyclical temporal variations in the community, and the methodology employed, which usually underestimates fish assemblages. The objective of this study was to describe short-scale and meso-scale (nycthemeral period and months, respectively) temporal variations in the ichthyofauna composition and structure of a sheltered beach of Baía Norte (Florianópolis, Santa Catarina state, Brazil), using a capéchade net. Samples were collected monthly for a period of 48 hours. During the period from December 2010 to November 2011, a total of 19,302 individuals belonging to 89 species and 39 families were captured. The number of individuals that were sampled during the day and/or night was dependent on the sampling month. On average, the daytime assemblage was more abundant and different in structure and composition than the nighttime assemblage. Of the eight species that had the highest Index of Relative Importance (%IRI), five had higher variations (ANOVA F) between the day and night than between the months. This finding reinforced the need for sampling during both the day and night. The capéchade net effectively captured demersal and pelagic individuals in a broad range of sizes