http://hdl.handle.net/10174/14297 2026-07-22T00:24:05Z 2026-07-22T00:24:05Z Noiva, João Brito, Pedro Rosa, Marcos Ribeiro, Carlos Terrinha, Pedro http://hdl.handle.net/10174/42330 2026-07-09T16:21:12Z 2026-05-31T23:00:00Z

Title: Occurrence and morphometric analysis of sorted bedforms on the Alentejo continental shelf, Southwestern Portugal. Authors: Noiva, João; Brito, Pedro; Rosa, Marcos; Ribeiro, Carlos; Terrinha, Pedro Abstract: The distribution of detrital sediments across continental shelves can provide important information on mineral concentrations, geological processes, and ecosystem substrates. On the southwestern Portuguese continental shelf, this distribution is governed by a complex interplay of hydrodynamic energy gradients, seafloor morphology, and eustatic sea-level changes. In particular, the strong energy gradient from the coastline to the shelf break, combined with open-ocean-wave dynamics, tidal regimes, and active continental uplift, determines the specific nature and grain size of submarine deposits. To better understand these dynamics, this study employed continuously recording geophysical methods, including multibeam echosounder bathymetry and backscatter, complemented by ultra-high-resolution seismic profiling and sediment sampling. Our results reveal four distinct depositional environments: homogeneous fine-grained sediments near the shelf break, sorted bedforms on the flat outer shelf, isolated sorted bedforms on the mid-shelf, and a homogeneous sand sheet near the coast. Notably, the presence of isolated bedforms at depths exceeding 80 meters suggests they are generated by wave action, reflecting the long-term impact of the Holocene sea-level rise over the last 8,000 years and possibly active mobilization under modern hydrodynamic conditions. Consequently, these findings highlight how high-resolution mapping can reveal sediment patterns and environmental histories that remain hidden through traditional discrete sampling.

2026-05-31T23:00:00Z Soares, Marta Cardoso, S.C. Anastácio, P.M. Banha, F. http://hdl.handle.net/10174/40752 2026-02-04T14:54:25Z 2025-01-01T00:00:00Z

Title: Preliminary observations of hunting behaviour by a freshwater threatened Leuciscidae Authors: Soares, Marta; Cardoso, S.C.; Anastácio, P.M.; Banha, F. Abstract: Freshwater ecosystems host diverse fish species that employ various foraging strategies, including hunting, a behaviour more commonly documented in marine environments. This study focuses on the threatened Iberian chub, Squalius pyrenaicus, in the Vascão River, Portugal, a species known for its opportunistic feeding. Using an underwater camera, we observed 45 predatory events in which S. pyrenaicus employed two tactics: solitary pursuit and group hunting. In group hunting, individuals coordinated attacks, encircling and taking turns pursuing prey. While all attacks seem unsuccessful, one feeding event was recorded where two S. pyrenaicus individuals interacted to capture a prey fish. Our findings suggest that S. pyrenaicus may rely on rudimentary social behaviors during solitary and group hunting, potentially influenced by environmental factors. This is the first report of such behaviour in this species, underscoring the need for further research into social and cognitive aspects of freshwater fish predation, particularly in light of ecosystem threats like invasive species and climate change.

2025-01-01T00:00:00Z Catarino, A. Mourinha, C. Custódio, M. Anastácio, P. Palma, P. http://hdl.handle.net/10174/40745 2026-02-04T12:43:22Z 2025-01-01T00:00:00Z

Title: Integrating Ecotoxicological Assessment to Evaluate Agricultural Impacts on Aquatic Ecosystems: A Case Study of the Lage Reservoir (Mediterranean Region) Authors: Catarino, A.; Mourinha, C.; Custódio, M.; Anastácio, P.; Palma, P. Abstract: This study analyzed the use of a toolbox to evaluate the impact of agricultural activity on the water quality/status classification of a hydro-agricultural reservoir (Lage reservoir, Southern Portugal). The framework integrated the quantification of a group of 51 pesticides and ecotoxicological endpoints with organisms from different trophic categories (the bacterium Aliivibrio fischeri, the microalga Pseudokirchneriella subcapitata, and the crustaceans Daphnia magna and Thamnocephalus platyurus) at two sampling points in the reservoir (Lage (L) and Lage S (LS)) between 2018 and 2020. Over the three-year study, we quantified 36 of the 51 pesticides analyzed in the Lage reservoir. Total concentrations increased successively from 0.95 µg L−1 to 1.99 and 2.66 µg L−1. Among these, the pesticides most frequently detected were terbuthylazine (100% of detection) and metolachlor (83% of detection), with maximum concentrations of 115.6 and 85.5 µg L−1, respectively. Samples from the LS site showed higher toxicity, where A. fischeri presented 30 min EC50 values of 39–51%. Microalgae growth was consistently inhibited, correlating with agricultural activity, mainly the application of herbicides and insecticides, while D. magna feeding rates revealed no inhibitory effects in the Lage samples. The results highlight that although the detected pesticide levels were below regulatory limits, they still induced toxic effects in the tested organisms. The potential ecological status of the reservoir was classified as moderate, and the integration of the proposal toolbox allowed refinement of the classification of water status. The results demonstrated that this integrated approach, combining multiple assessment methods, establishes a more robust water quality evaluation methodology, allowing it to be used as a tool complementary to the WFD methodology. This proposal not only identified existing pollution impacts but also enabled (1) early detection of the toxic effects of emerging contaminants to prevent ecological damage; (2) proactive management through specific actions to restore water status; and (3) improved sustainable water use. Keywords: Alqueva project; bioassays; irrigation agriculture; water status classification; Water Framework Directive

2025-01-01T00:00:00Z Anastacio, P. Ribeiro, F. Chainho, P. http://hdl.handle.net/10174/40744 2026-02-04T12:40:14Z 2025-01-01T00:00:00Z

Title: Invasions in aquatic systems: Patterns, mechanisms and management Authors: Anastacio, P.; Ribeiro, F.; Chainho, P. Abstract: The 13th NEOBIOTA International Conference on Biological Invasions (NEOBIOTA 2024), held in Lisbon, Portugal, from 3–6 September 2024, brought together 421 participants from 47 countries for one of the most significant global gatherings in invasion science. Notably, this meeting featured the strongest representation of aquatic studies to date, spanning marine and freshwater systems across oral sessions, posters and workshops. This momentum contributed to the creation of a dedicated Special Issue, incorporating contributions from both conference participants and other aquatic researchers. This Special Issue on Invasions in Aquatic Systems comprises 23 papers — original research and reviews — organised into five themes: Responses to Environmental Stressors, Ecological Interactions and Invasion Impacts, Detection and Monitoring Tools, Management and Policy and Global and Regional Syntheses (Fig. 1). Collectively, these papers provide a data-rich snapshot of a rapidly evolving field and the challenges it faces.

2025-01-01T00:00:00Z