The Anthropocene is characterized by dramatic ecosystem changes driven by human activities. The impact of these activities can be assessed by different geochemical and paleontological proxies. However, each of these proxies provides only a fragmentary insight into the effects of anthropogenic impacts. It is highly challenging to reconstruct, with a holistic view, the state of the ecosystems from the preindustrial period to the present day, covering all biological components, from prokaryotes to multicellular eukaryotes. Here, we used sedimentary ancient DNA (sedaDNA) archives encompassing all trophic levels of biodiversity to reconstruct the two century-natural history in Bagnoli-Coroglio (Gulf of Pozzuoli, Tyrrhenian Sea), one of the most polluted marine-coastal sites in Europe. The site was characterized by seagrass meadows and high eukaryotic diversity until the beginning of the 20th century. Then, the ecosystem completely changed, with seagrasses and associated fauna as well as diverse groups of planktonic and benthic protists being replaced by low diversity biota dominated by dinophyceans and infaunal metazoan species. The sedaDNA analysis revealed a five-phase evolution of the area, where changes appear as the result of a multi-level cascade effect of impacts associated with industrial activities, urbanization, water circulation and land-use changes. The sedaDNA allowed to infer reference conditions that must be considered when restoration actions are to be implemented.

Marine organisms with fast growth rates and great biological adaptive capacity might have biotechnological interests, since ecological competitiveness might rely on enhanced physiological or biochemical processes’ capability promoting protection, defense, or repair intracellular damages. The invasive seagrass Halophila stipulacea, a non-indigenous species widespread in the Mediterranean Sea, belongs to this category. This is the premise to investigate the biotechnological interest of this species. In this study, we investigated the antioxidant activity in vitro, both in scavenging reactive oxygen species and in repairing damages from oxidative stress on the fibroblast human cell line WI-38. Together with the biochemical analysis, the antioxidant activity was characterized by the study of the expression of oxidative stress gene in WI-38 cells in presence or absence of the H. stipulacea extract. Concomitantly, the pigment pool of the extracts, as well as their macromolecular composition was characterized. This study was done separately on mature and young leaves. Results indicated that mature leaves exerted a great activity in scavenging reactive oxygen species and repairing damages from oxidative stress in the WI-38 cell line. This activity was paralleled to an enhanced carotenoids content in the mature leaf extracts and a higher carbohydrate contribution to organic matter. Our results suggest a potential of the old leaves of H. stipulacea as oxidative stress damage protecting or repair agents in fibroblast cell lines. This study paves the way to transmute the invasive H. stipulacea environmental threat in goods for human health.

This paper presents field experiments of mineral deposition on steel, induced by cathodic polarization in natural seawater, as a sustainable strategy for the life extension of marine steel structures. Although this approach is quite well known, the ability of the mineral deposit to both protect steel from corrosion in the absence of a cathodic current, thus operating as an inorganic coating, and provide an effective substrate for colonization by microorganisms still needs to be fully explained. To this end, two identical steel structure prototypes were installed at a depth of 20 m: one was submitted to cathodic polarization, while the other was left under free corrosion for comparison. After 6 months, the current supplied to the electrified structure was interrupted. A multidisciplinary approach was used to analyze the deposits on steel round bars installed in the prototypes over time, in the presence and in the absence of a cathodic current. Different investigation techniques were employed to provide the following information on the deposit: the composition in terms of elements, compounds and macro-biofouling; the morphology; the thickness and the degree of protection estimated by electrochemical impedance spectroscopy (EIS). The results showed that under cathodic polarization, the thickness of the deposit increased to 2.5 mm and then remained almost constant after the current was interrupted. Conversely, the surface impedance decreased from 3 kΩ cm² to about 1.5 kΩ cm² at the same time, and the aragonite–brucite ratio also decreased. This indicates a deterioration in the protection performance and soundness of the deposit, respectively. Considering the trends in thickness and impedance together, it can be concluded that the preformed mineral deposit does not undergo generalized deterioration after current interruption, which would result in a reduction in thickness, but rather localized degradation. This phenomenon was attributed to the burrowing action of marine organisms, which created porosities and/or capillary pathways through the deposit. Therefore, the corrosion protection offered by the mineral deposit without a cathodic current is insufficient because it loses its protective properties. However, the necessary current can be quite limited in the presence of the deposit, which in any case provides a suitable substrate for sustaining the colonization and growth of sessile marine organisms, thus promoting biodiversity.

Viruses are the most abundant ‘biological entities’ in the world’s oceans. However, technical and methodological constraints limit our understanding of their diversity, particularly in benthic abyssal ecosystems (>4000 m depth). To verify advantages and limitations of analyzing virome DNA subjected either to random amplification or unamplified, we applied shotgun sequencing-by-synthesis to two sample pairs obtained from benthic abyssal sites located in the North-eastern Atlantic Ocean at ca. 4700 m depth. One amplified DNA sample was also subjected to single-molecule long-read sequencing for comparative purposes. Overall, we identified 24,828 viral Operational Taxonomic Units (vOTUs), belonging to 22 viral families. Viral reads were more abundant in the amplified DNA samples (38.5–49.9%) compared to the unamplified ones (4.4–5.8%), with the latter showing a greater viral diversity and 11–16% of dsDNA viruses almost undetectable in the amplified samples. From a procedural point of view, the viromes obtained by direct sequencing (without amplification step) provided a broader overview of both ss and dsDNA viral diversity. Nevertheless, our results suggest that the contextual use of random amplification of the same sample and long-read technology can improve the assessment of viral assemblages by reducing off-target reads.