Percorrer por autor "Souza-Kasprzyk, Juliana"
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- Differential elemental accumulation of the signal crayfish (Pacifastacus leniusculus) along an invasion gradientPublication . Gonçalves, Diana; Sousa, Ronaldo; Souza-Kasprzyk, Juliana; Niedzielski, Przemyslaw; Teixeira, Amilcar; Padilha, Janeide de Assis GuilhermeThe non-native signal crayfish (Pacifastacus leniusculus) can influence elemental cycling in aquatic ecosystems through bioaccumulation and transfer of chemical elements, with potential spatial variation along invasion gradients. In this study, we investigate the differences in elemental exposure in signal crayfish in the Rabaçal River, Portugal. We focus on potential intra-population differences along a well-defined invasion gradient, comparing individuals from the invasion core (upstream) and the downstream expanding front (n = 30 each). We examined 57 elements in the muscle of the signal crayfish, including essential elements (EEs): Mn, Co, Ni, Cu, Zn, Mg, Ca, Fe, Se, V, S; non-essential and potentially toxic elements (PTEs): Cd, Hg, Pb, U, As, Sr, Ba, Cr, Zr, Cs, Tl; and technology-critical elements (TCEs): Ti, Rb, La, Ce, Pr, Gd, Dy, Ho, Er, Yb, Ga, Ge, Hf, Ta, In, Re, Te, Pt. We explored the relationship between element concentrations and signal crayfish trophic ecology, inferred through stable isotope analysis (613C and 615N), behaviour, and epibiotic associate load-factors known to shape invasion success through their effects on resource acquisition, competition, and physiological stress. Significant differences in element concentrations were found between individuals from the core and front. Individuals from the front showed higher levels (mean mu g/kg, dry weight) of Co: (476 vs. 297), V: (390 vs. 262), Mn: (2.6 x 104 vs. 1.0 x 104), Hg: (2526 vs.1658), andTa: (21 vs. 11). These patterns suggest that front individuals, with higher 615N values and more exploratory behaviour, feed at higher trophic levels (e.g., macroinvertebrates), which may explain the elevated concentrations of biomagnifying elements such as Hg and Ta. On the other hand, individuals from the core had higher levels of Pb: (361 vs. 234), and Sr: (39772 vs. 20018), likely due to a diet based on basal resources, as supported by the strong negative correlation between Pb and 613C, indicating reliance on benthic sources more prone to lead accumulation. This study increases our understanding of contaminant accumulation along an invasion gradient, offering insights for management practices-such as targeted removal of highly contaminated individuals, improved monitoring of metal levels in invaded areas, and public awareness campaigns-to minimise ecological impacts on higher trophic levels.
- First multi-contaminant assessment of the non-native American mink (Neogale vison) in Iberian freshwater ecosystemsPublication . Lages, Bárbara; Sousa, Ronaldo; Cunha, Sara C.; Souza-Kasprzyk, Juliana; Fernandes, José O.; Gámez, Alejandro Nieto; Nóvoa, Miguel Fernandes; Guedes, Américo; Alves, Pedro; Niedzielski, Przemyslaw; Cortez, José Paulo; Sargo, Roberto; Garcês, Andreia; Loureiro, Filipa; Teixeira, Amilcar; Padilha, JaneideNon-native predators can act simultaneously as stressors and sentinels of environmental quality. This study aimed to quantify multi-contaminant burdens, characterize tissue-specific accumulation patterns, and evaluate the influence of biological factors (sex and body size) and trophic ecology (δ¹³C, δ¹⁵N) on contaminant exposure in 49 American mink (Neogale vison) collected during control campaigns (2023–2024) from two freshwater ecosystems in northern Portugal Angueira and Maçãs. We quantified legacy contaminants, including polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO-BDEs) in liver, together with essential (EEs), potentially toxic (PTEs), and emerging technology-critical (TCEs) elements in kidney, muscle, and fur. Thirteen PBDE and MeO-BDE congeners and 63 elements were determined to characterize multi-contaminant burdens and tissue-specific accumulation patterns, and stable isotopes (δ¹³C, δ¹⁵N) to assess trophic position and contaminant–diet relationships. Liver ∑PBDE (0.0712 ng g⁻¹ w.w.) and ∑MeO-BDE (0.0645 ng g⁻¹ w.w.) concentrations were low compared with other regions or controlled exposure studies, suggesting limited regional inputs of these contaminants in the study area. No sex-related differences were detected. Fur accumulated most EEs and several PTEs (e.g., As, Sr), supporting its value as a non-invasive matrix. Stable isotopes indicated similar trophic positions between sexes (δ¹³C ≈ –25‰; δ¹⁵N ≈ 12‰) with moderate trophic niche overlap (38%). Weak-to-moderate positive correlations between δ¹ ⁵N and some PBDE congeners suggest a potential trophic dietary contribution to exposure. Overall, American mink accumulated multiple contaminant classes at relatively low levels, with exposure mainly influenced by local environmental conditions and diet. Given that American mink individuals are routinely culled during management programs, our findings support their use as a multi-contaminant sentinel and highlight fur and liver as practical matrices for freshwater monitoring.