Vítor Gonçalves

Ten years of dedicated biodiversity research and coordinated open-data publication have built an extensive, reusable knowledge base for the Azores. We synthesize this collective achievement through the AZORES BIOTA and BioMonI-Plot collections, evaluating its contribution to addressing the Wallacean and Prestonian shortfalls and identifying priorities for future research and monitoring. Focusing on the nine islands of this North Atlantic archipelago, we review publications issued between 2016 and May 2026, encompassing terrestrial and marine organisms across six kingdoms. We combine curated publication and dataset metadata with Darwin Core occurrenceID-linked species and subspecies records to assess spatial, taxonomic, temporal and methodological coverage, species accumulation by colonization status, and island species–area relationships. Across 91 publications, the collections document 931 animal, 1,185 plant and 742 fungal species and subspecies, alongside taxa from three additional kingdoms, and identify 598 additions to the Azorean Biodiversity Portal reference list. This sustained effort has substantially expanded accessible knowledge of species distributions, contributing to reducing the Wallacean shortfall. Arthropod abundance datasets and repeated standardized surveys also alleviate the Prestonian shortfall by enabling assessments of population and community change. Together, these resources establish valuable baselines for biodiversity assessment, invasion surveillance and conservation planning. The synthesis also reveals uneven coverage among islands, taxa and habitats, with spatial differences in research effort complicating interpretation of species–area relationships. The Azorean experience demonstrates the substantial scientific value of sustained regional expertise, collaboration and standardized open-data publication for understanding island biodiversity. By consolidating achievements and making remaining gaps explicit, this synthesis provides a foundation for targeted investment in underrepresented biota, spatially balanced surveys and sustained abundance monitoring, strengthening the evidence base for future biodiversity research and conservation.

Biological dinitrogen (N2) fixation is increasingly recognized as an important source of nitrogen in freshwater ecosystems; however, the magnitude and drivers of this process are poorly quantified at the global scale. This limited understanding stems from a historical focus on cyanobacterial diazotrophs in a limited number of regions, obscuring the true magnitude, community composition, and environmental drivers of freshwater diazotrophy. This study presents the first standardized global assessment quantifying diazotroph abundance, N2 fixation rates, and nifH gene diversity at 206 freshwater sites across 36 countries on five continents. Diazotrophs were ubiquitous across freshwater ecosystems, comprising up to 16% of the total bacterial abundance, with N2 fixation rates spanning more than 5 orders of magnitude (0.001–133 nmol N L-1 d-1). Noncyanobacterial diazotrophs (NCDs) dominated these communities at 85% of the sites, challenging the cyanobacteria-centric paradigm. Multilinear regression models revealed that water temperature is a key regulator of diazotrophy, delineating distinct regimes for N2 fixation rates (21°C) and the relative abundance of NCDs (9°C). These models further indicated that warmer conditions may reduce the relative abundance of NCDs while favoring cyanobacterial diazotrophs. Ultimately, these thermally defined regimes highlight that warming freshwater environments would change the physicochemical and community drivers that currently regulate freshwater N2 fixation patterns, with major implications for nitrogen cycling models.

On remote oceanic islands, changes in land uses frequently involve the clearance of native forest, establishment of exotic commercial plantations and intensification of agricultural and livestock activities. These transformations often result in the alteration or removal of native riparian vegetation, with potentially strong effects on stream ecosystem structure and function. Aquatic decomposers and organic matter decomposition are particularly sensitive to land uses changes due to their dependence on terrestrial litter inputs. Here we assessed organic matter decomposition, and associated aquatic hyphomycetes and macroinvertebrates in Azorean streams under riparian forest modifications (cryptomeria plantations and pastures) in comparison with non‐impacted streams (native laurel vegetation). Ochroma pyramidale wood and Clethra arborea leaves were used as substrates enclosed in fine‐ and coarse‐mesh bags to assess organic matter decomposition driven by microbes alone and by the combined activity of microbes and macroinvertebrates, respectively. We found that organic matter decomposition was faster in streams surrounded by pastures due to higher dissolved nutrient concentrations and water temperature, while streams flowing through native riparian vegetation and cryptomeria plantations showed similar organic matter decomposition. Leaf decomposition was faster in coarse‐ than in fine‐mesh bags only in streams adjacent to cryptomeria plantations, a pattern associated with the higher shredder abundance compared with the other streams. Moreover, leaves decomposed faster than wood due to their lower toughness and greater susceptibility to biological degradation. Aquatic hyphomycete taxa richness was lower in pasture streams, but their reproductive activity did not significantly differ among stream types. Benthic macroinvertebrate taxa richness and abundance did not significantly differ among stream types. These findings highlight the complex interactions between land‐use transformation and organic matter decomposition processes emphasizing the importance of riparian management for maintaining ecosystem functioning. Moreover, our findings underscore the vulnerability of stream ecosystem functioning to riparian land‐use change on remote oceanic islands, where even moderate alterations in riparian vegetation can significantly affect key ecological processes.

Water-laden sedimentary archives, such as marine and lacustrine sequences, have revolutionised the reconstruction of eruptive histories, as they usually hold a richer and more continuous tephra record when compared to subaerial environments. Here, we explore peatlands as another sedimentary archive from which highly detailed tephrostratigraphies can be obtained. Peat sequences have the advantage of being logistically easier and cheaper to access than other water-laden sequences, and more readily amenable to radiocarbon dating than terrestrial sequences. Pico Island in the Azores Archipelago provides an ideal laboratory to test the potential of peatlands as high-resolution sedimentary archives. The island is characterised by numerous basaltic monogenetic cones, yet its tephrostratigraphy remains poorly constrained, as such eruptions typically generate small tephra dispersals, and the resulting deposits are difficult to date. Taking advantage of the ubiquitous peatlands found in the Pico central uplands (above ~600 m altitude), a coring campaign was carried out in July 2025. Eight peatlands were cored using a Russian corer and a UWITEC® piston corer installed on a platform raft. Peatland basins were surveyed using a DJI Mavic 2 drone to produce high-resolution georeferenced digital surface models. Recovered cores were opened and logged at the University of the Azores, where peat, lacustrine, and volcanic facies (tephra horizons) were identified. Loss on ignition (LOI) was determined throughout the sedimentary sequences, and their bases were radiocarbon dated. Here, we present the stratigraphic sequences of the four main peatlands: Caiado and Barreira cone craters, and Peixinho and Lavandeira inter-cone depressions. All four stratigraphic sequences contain numerous tephra horizons, ranging in thickness from less than 1 mm up to several tens of centimetres. The thickest tephra horizons are found at the sites located in the eastern sector (Peixinho and Caiado), whereas thinner horizons predominate at the western sites (Lavandeira and Barreira). Most tephra horizons correspond to primary fall deposits, with only a minor portion of reworked materials. Radiocarbon dating reveals maximum sequence ages of 8608-8514 cal yr BP (Caiado), 6558-6399 cal yr BP (Lavandeira), 5588-5474 cal yr BP (Barreira), and 2181-2046 cal yr BP (Peixinho). The bases of the Barreira and Caiado sequences consist of weathered subaerial scoria deposits, interpreted as pre-lacustrine substrate. Lower LOI values, typically found in the lower part of the sequences, suggest initial lacustrine conditions, whereas higher LOI values in the upper part of the records indicate the transition to peatland. Ongoing work will focus on systematic radiocarbon dating below primary tephra horizons and geochemical characterisation of volcanic glass shards, enabling a high-resolution temporal and spatial reconstruction of Pico’s Holocene eruptive history. This work was supported by Fundação para a Ciência e a Tecnologia (FCT) through project ExTRAP (https://doi.org/10.54499/2023.12382.PEX).

Cyanobacteria are rich producers of secondary metabolites, excreting some of these to the culture media. However, the exometabolome of cyanobacteria has been poorly studied, and few studies have dwelled on its characterization and bioactivity assessment. In this work, exometabolomes of 56 cyanobacterial strains were characterized by HR-ESI-LC-MS/MS. Cytotoxicity was assessed on two carcinoma cell lines, HepG2 and HCT116, while the reduction in lipids was tested in zebrafish larvae and in a steatosis model with fatty acid-overloaded human liver cells. The exometabolome analysis using GNPS revealed many complex clusters of unique compounds in several strains, with no identifications in public databases. Three strains reduced viability in HCT116 cells, namely Tolypotrichaceae BACA0428 (30.45%), Aphanizomenonaceae BACA0025 (40.84%), and Microchaetaceae BACA0110 (46.61%). Lipid reduction in zebrafish larvae was only observed by exposure to Dulcicalothrix sp. BACA0344 (60%). The feature-based molecular network shows that this bioactivity was highly correlated with two flavanones, a compound class described in the literature to have lipid reduction activity. The exometabolome characterization of cyanobacteria strains revealed a high chemodiversity, which supports it as a source for novel bioactive compounds, despite most of the time being overlooked.

This paper presents an annotated checklist of the Basidiomycota taxa (including lichenicolous fungi and the subdivision Pucciniomycotina) from the Azores archipelago and reviews the published records to account for their taxonomic status. The number of Basidiomycota species recorded in the Azores has increased considerably during the 20th century and now stands at 544 species. This study provides distribution data and includes changes in the nomenclature of the listed taxa. Sampling campaigns contributed to 116 new records of Basidiomycota for the Azores archipelago. In addition, there were new records for eight islands: 162 species found for the first time on São Miguel Island, 55 species new to Santa Maria Island, 33 species new to Flores Island, 15 species new to Terceira Island, 9 species new to Pico Island, 17 species new to São Jorge Island, 4 species new to Graciosa Island, and 2 species new to Corvo Island. The transformation of vegetation cover in the archipelago has been very drastic, and this is reflected in the presence of many foreign fungal species on the islands. From these data, we conclude that within Macaronesia, the diversity of Basidiomycota in the Azores is more similar to that in Madeira than in the Canary Islands.

Coccoid cyanobacteria represent an important part of cyanobacterial freshwater diversity, with many studied strains in public databases identified as Synechococcus. This is a diverse genus, both morphologically and ecologically, with a global distribution. However, many of the so-called Synechococcus-like cyanobacteria strains could represent several independent genera that require further studies. In this work, four strains of a Synechococcus-like cyanobacteria isolated from freshwater lakes and terrestrial atmophytic habitats on São Miguel and Flores Islands (Azores archipelago) were studied genetically using the 16S rRNA and 16S–23S rRNA ITS, morphologically with light and transmission electron microscopy, and ecologically. A draft genome was produced from the reference strain by Illumina sequencing, which allowed a more complete phylogenetic study and a deeper taxonomic analysis, revealing a divergent phylogenetic evolution and low ANI and AAI values (69.4% and 66.3%, respectively) to Thermosynechococcus, the closest phylogenetic genus. Although morphologically similar to Synechococcus, the 16S rRNA and genome phylogenetic analysis placed the studied strains in a clade sister to Thermosynechococcus, inside the Thermosynechococcaceae. Thus, Pseudocalidococcus azoricus gen. sp. nov. is described as a new coccoid freshwater genus and species from the Azores archipelago. A detailed comparison with similar morphological taxa is provided, supporting the separation of the new genus. The 16S rRNA with a high genetic similarity to other strains from several continents identified as Synechococcus sp. suggests that the new genus probably has a worldwide distribution. Future studies should be performed to clarify the taxonomic identity of those strains.