Instituto de Fomento Pesquero

Environmental filtering studies have revealed immense oceanic microbial diversity, yet the Southeast Pacific remains comparatively undersampled. We characterize the molecular diversity of phytoplankton across two biogeographic domains with contrasting oceanography—fjords and channels (41–53° S) versus the open Pacific (36–42° S)—where the frequency and intensity of harmful algal blooms (HABs) have increased. Using SSU rRNA metabarcoding, we retrieved community composition and biogeographic patterns for micro-phytoplankton. Diversity signals indicated broadly overlapping communities between domains with subtle shifts along hydrographic and nutrient gradients rather than sharp breaks. Phylogenetic resolution within bloom-forming genera recovered well-supported clades, and multiple ASVs matched historically relevant HAB taxa, including representatives of the Alexandrium complex, Dinophysis, Pseudo-nitzschia, and Karenia. Together, these results suggest that regional environmental filtering acts modestly at the community level while preserving clear signals of taxa of management concern. By providing a regionally resolved, DNA-based baseline for southern Chile’s fjords and adjacent open coast, this study helps fill the molecular diversity gap for the Southeast Pacific and supports improved HAB surveillance and ecosystem forecasting in a climate-sensitive seascape.

In southern Chile, harmful algal blooms (HABs) pose a threat to public health, artisanal fisheries, and the aquaculture industry (mussels and salmon). However, little is known about the environmental factors contributing to outbreaks of HABs in fjord systems. In summer 2017, an oceanographic cruise was carried out to study the physical processes associated with a bloom of the dinoflagellate Karenia spp. in the Gulf of Penas and Taitao Peninsula, Chilean Patagonia, causing a massive mortality of salmon (approximately 170,000 fish, worth USD 390,000). Satellite images from Sentinel-3 were utilized to distinguish between areas with high and low densities of Karenia cells. Cell densities were highest in the waters of the northern Taitao Peninsula (70 × 103 cells L−1), and lowest at the Gulf of Penas. Support vector classification (SVC) based on bands 1 (400 nm), 2 (412.5 nm), and 6 (560 nm) from the Sentinel-3 images and the normalized fluorescence line height (FLH) classified bloom presence/absence with an 83% coincidence rate. The SVC model correctly identified non-bloom areas, with limited false positives, and successfully captured bloom zones where Karenia densities were highest. These results demonstrate the importance of incorporating satellite tools in the design and implementation of monitoring programs for the early detection of HABs, particularly in remote, difficult-to-access areas.

In northern Chile, the persistent presence of tropical fish in coastal waters has been observed, even without El Niño–Southern Oscillation (ENSO) events. Species such as Sphyraena ensis Jordan & Gilbert, 1882 and Galeichthys peruvianus Lütken, 1874 have been recorded in suboptimal environments, suggesting a possible ecological reconfiguration. This anomaly could be linked to global warming, as species typical of warm waters are found in colder areas, highlighting a sustained increase in sea temperature. These records provide new evidence of the poleward range expansion of tropical fish species, likely driven by long‑term ocean warming.

This study introduces an innovative approach to the long-standing challenge of determining the animal origin of blood used in artworks - an issue of central relevance to art historians aiming to understand historical techniques, symbolic meanings, and the cultural traditions associated with artistic materials. Using LC-MS/MS analysis, species-specific peptide sequences of blood proteins were identified, allowing for the discrimination of seven animal species (cat, cow, dog, goose, hen, human, and pig). This analytical approach was successfully applied to a series of model samples containing blood, confirming both the proteinaceous composition and the animal origin of the blood. Furthermore, the method enabled the identification of pig blood in historical samples taken from Japanese and Chinese lacquer artefacts dating from the 18th and 19th centuries. The novelty of this work lies in a new strategy for data evaluation that facilitates the creation of custom peptide databases tailored to distinguish specific animal species. This approach overcomes a major limitation in proteomic studies - namely, the lack of complete sequence data for many animals - by incorporating homologous sequences from closely related species. The strategy demonstrates a high degree of effectiveness when implemented within a clearly defined group of animal species, such as those historically utilised in the production of blood-based artistic materials. This approach offers a novel pathway for the molecular identification of animal origin in cultural heritage contexts and establishes a robust foundation for future interdisciplinary investigations bridging art history, conservation science, and molecular biology.

Ecosystems are undergoing global changes that disrupt energy transfer across trophic levels, reducing energy availability and destabilizing predator–prey interactions. In marine systems, small pelagic fish (SPF) are key energy vectors to higher trophic levels. In the Bay of Biscay, common dolphins rely heavily on SPF, which have declined in size and condition in recent decades, while dolphin by-catch has increased. To explore whether prey field changes could explain shifts in dolphin distribution, we mapped prey energy by integrating biomass, size and energy content for four SPF species (sardine, anchovy, sprat and small horse mackerel), representing 80% of the dolphin diet. We analysed acoustic survey data from PELGAS (2000–2023) and JUVENA (2009–2023) to assess temporal and spatial changes in prey energy. Energy per prey has declined, mainly due to decreasing fish length and energy density. Total energy available for common dolphin remained stable, through increase of lower-energy anchovies and decrease of larger, higher-energy sardines. Spatial redistributions were also evident, with sardine energy becoming more coastal and anchovy energy expanding northward. These energy seascapes dynamics, probably climate-driven, may have led dolphins to forage closer to shore, in areas of higher fishing pressure, thereby contributing to the recent rise in by-catch.

Selection, dispersal and drift jointly contribute to generating variation in microbial composition within and between hosts, habitats and ecosystems. However, we have limited examples of how these processes interact as hosts and their microbes turn over across latitudinal gradients of biodiversity and climate. To bridge this gap, we assembled an extensive dataset of 580 skin bacteriomes from 22 amphibian species distributed across a 10° latitudinal range in Chile. Amphibians are susceptible to the fungal pathogen Batrachochytrium dendrobatidis (Bd), which infects their skin, potentially leading to changes in the normal skin microbiome (i.e., dysbiosis). Using comparative methods, accounting for pathogen infection and implementing resampling schemes, we found evidence of phylosymbiosis, characterised by more similar bacterial communities in closely related amphibian species. We also compared how neutral processes affected the assembly of skin bacteria by focusing on two widespread species from our dataset: the Chilean four-eyed frog (Pleurodema thaul) and Darwin's frog (Rhinoderma darwinii). Neutral models revealed that dispersal and chance largely facilitated the occurrence of ~90% of skin bacteria in both species. Deterministic processes (e.g., phylosymbiosis, active recruitment of microbes, microbe-microbe interactions) explained the remaining fraction of the bacteriomes. Amphibian species accounted for 21%-32% of the variance found in non-neutral bacterial taxa, whereas the interaction with Bd carried a weaker but still significant effect. Our findings provide evidence from ectotherms that most of their skin bacteria are subject to dispersal and chance, yet contemporary and historical contingencies leave strong signatures in their microbiomes even at large geographical scales.