Horizontal distribution of deep sea microplankton: A new point of view for marine biogeography.

An investigation on microplankton composition and spatial distribution has been carried out around Italian seas. The analysis of 53 samples, collected in 2017 at two depths in 27 different stations, has led to a scenario of horizontal distribution of microplankton. Dinophyta and Ciliophora were chosen as representatives of the whole microplankton community. A total of 60 genera were identified. Cluster analysis of data regarding taxa presence and abundance led us to recognize that similarities between surface stations were more evident than those between deep ones. Furthermore, we conducted an inter-annual comparison with available data from the South Adriatic Sea (2013, 2015). The higher dissimilarity between deep sea samples was also confirmed in a relatively smaller geographic area. The dissimilarity of deep-sea samples does not correspond to a higher habitat diversification, in terms of abiotic parameters. It has been suggested that the negligible biological connectivity in the deep, for those micro-organisms not able to perform wide spatial migrations, could produce such a biological diversificatio

Hybrid Gene Origination Creates Human-Virus Chimeric Proteins during Infection

RNA viruses are a major human health threat. The life cycles of many highly pathogenic RNA viruses like influ-enza A virus (IAV) and Lassa virus depends on host mRNA, because viral polymerases cleave 50-m7G-cappedhost transcripts to prime viral mRNA synthesis (‘‘cap-snatching’’). We hypothesized that start codons withincap-snatched host transcripts could generate chimeric human-viral mRNAs with coding potential. We reportthe existence of this mechanism of gene origination, which we named ‘‘start-snatching.’’ Depending on thereading frame, start-snatching allows the translation of host and viral ‘‘untranslated regions’’ (UTRs) to createN-terminally extended viral proteins or entirely novel polypeptides by genetic overprinting. We show thatboth types of chimeric proteins are made in IAV-infected cells, generate T cell responses, and contributeto virulence. Our results indicate that during infection with IAV, and likely a multitude of other human, animaland plant viruses, a host-dependent mechanism allows the genesis of hybrid genes

The Spatial Distribution of Copepod Functional Traits in a Highly Anthropized Mediterranean Coastal Marine Region

Copepods dominate marine zooplankton in abundance and play key roles in pelagic food webs. These small crustaceans show high taxonomic and functional diversity. Although there has been considerable research on their taxonomy, only a few studies have focused on their functional traits. In this study, we analyzed the functional traits of 95 copepod species, considering their body size, trophic regime, feeding behavior, and spawning strategy. Based on samples collected during two surveys (autumn 2020 and summer 2021) located in the coastal waters of three gulfs (Gaeta, Naples, and Salerno) in the highly populated Campania region (the central Tyrrhenian Sea, NW Mediterranean), we identified nine functional groups of copepods with different characteristics. The group that comprised herbivorous copepods with feeding currents and a broadcast strategy was the most abundant in both seasons and all gulfs. This group was dominated by Acartia clausi, Centropages typicus, Temora stylifera, and the Paracalanus parvus complex. The other functional groups showed differences in their temporal and spatial distribution. Our study reports the functional diversity of copepods along the Campania coast, thus contributing to advancing our knowledge of the planktonic trophic structure in a region of considerable importance due to its marine resources and services

Disentangling the hidden microzooplankton diversity integrating microscopy and multigene high-throughput sequencing

Comunicación presentada a las ASLO Aquatic Sciences Meeting 2023 4-9 junio 2023 (Palma de Mallorca). - Scientific Sessions SS061 Novel Molecular Tools To Assess Biodiversity and Resilience of Aquatic EnvironmentsMicroplankton is an heterogeneous group of organisms ranging between 20 and 200 microns in size. Morphological characterization of its diversity is challenging as it includes Chromista, Protozoa, and Metazoa (adults and larvae). We characterized the composition of the microzooplankton community (heterotrophic and mixotrophic) collected with a CalVET net (50 µm mesh), in a coastal area affected by urban wastewater discharges in the N Alboran Sea (SW Mediterranean). We applied an integrative taxonomic approach, combining metabarcoding of the mtDNA cytochrome oxidase I (COI) and the V4 region of the 18S rRNA (18S) genes with morphological microscopic identification of organisms. Both methods showed differentiated coastal and offshore microzooplankton assemblages. The dominant taxa varied depending on the method used, with Dinophyceae accounting for 64-85% of the microscopy counts but Arthropoda representing up to 98% or the COI and 18S reads. When computing Protozoa and Metazoa relative abundances separately, both microscopy and metabarcoding revealed unicellular communities dominated by thecate Dinophyceae, followed by Ciliophora. Metazoa microscopy counts were dominated by eggs, followed by Copepoda nauplii in offshore waters, whilst by Appendicularia and Mollusca larvae in the shallow coastal stations. COI reads also corresponded mostly to Copepoda and Mollusca. However, 18S reads were dominated by Thecostraca and Copepoda. Despite the identification level differed among methods and taxa, the integrated approach revealed higher diversity than expected

Characterization of microzooplankton communities in a polluted coastal area integrating high-throughput sequencing and microscopy

The Mediterranean Sea is subjected to strong anthropogenic pressures that may be causing important ecosystem changes, particularly in coastal areas under high anthropogenic pressure. We characterized the composition of the microzooplankton community in a coastal area in the N Alboran Sea (SW Mediterranean) highly impacted by urban wastewater pollution. Two offshore outfalls release urban wastewater to the sea at a 40 m bottom depth, from a nearby town. We applied an integrative taxonomic approach, combining metabarcoding of the mitochondrial COI and the 18S rRNA genes with morphological microscopic identification of organisms, collected with a CalVET net (50 µm mesh). Hydrology was notably affected near the bottom at the vicinity of the submarine emissaries exit, presenting increased temperature and turbidity, and decreased salinity due to the urban freshwater discharge. Nutrient concentrations exceeded the Water Framework Directive limits; however, chlorophyll a concentrations were not very high, due to strong water column stratification. Microzooplankton communities (50-200 µm) were dominated by dinoflagellates (50-80% relative abundance), followed by copepods (copepodites and nauplii), eggs and cysts. We found significant differences in communities’ composition between the coastal shallow area and the offshore waters, driven by pollution and stratification.Consejería de Economía, Innovación y Ciencia de la Junta de Andalucía; Unión Europea, Fondo Europeo de Desarrollo Regional (P20_00743

The Distribution of <i>Pseudodiaptomus marinus</i> in European and Neighbouring Waters—A Rolling Review

Among non-native copepods, the calanoid Pseudodiaptomus marinus Sato, 1913 is the species probably spreading at the fastest pace in European and neighbouring waters since its first record in the Adriatic Sea in 2007. In this contribution, we provide an update on the distribution of P. marinus in the Mediterranean and Black Seas, along the Atlantic coasts of Europe, in the English Channel and in the southern North Sea. Starting from a previous distribution overview, we include here original and recently (2019–2023) published data to show the novel introduction of this species in different geographical areas, and its secondary spreading in already colonised regions. The picture drawn in this work confirms the strong ability of P. marinus to settle in environments characterised by extremely diverse abiotic conditions, and to take advantage of different vectors of introduction. The data presented allow speculations on realistic future introductions of P. marinus and on the potential extension of its distribution range