Nematodes represent >3/5 of the abundance of the world’s metazoans and usually account for nearly 90% of the total benthic fauna, playing a key ecological role in the benthic ecosystem functioning on a global scale. These small metazoans include a relevant number of microscopic predators and, in turn, are the most abundant preys of macro-megafauna and fish juveniles thus playing a key role in marine food webs. Here, using two independent approaches, we test the bioaccumulation in marine nematodes of several heavy metals present in contaminated sediments. We report here that nematodes, despite their short life cycle and small size, bioaccumulate significantly heavy metals. Bioaccumulation increases from deposit feeders and microalgal grazers to predators of microbes and other tiny metazoans. These results suggest that nematodes also contribute to their biomagnification along the food webs and can contribute to increase the transfer of contaminants from the sediments to larger organisms.

Marine nematodes possess all the prerequisites to serve as “simpler models” for investigating biological phenomena and are gaining attention as emerging model organisms. This review evaluates their potential to address diverse biological questions regarding ecosystem functioning, climate change adaptation, host–microbe interactions, ecotoxicology, and biotechnological applications. Among the reviewed taxa, Litoditis marina and select Monhysteridae species, such as Diplolaimella dievengatensis, Halomonhystera disjuncta, and Diplolaimelloides spp., emerge as leading candidates due to their manageable life cycles, adaptability to laboratory conditions, and available genomic resources. These tiny organisms provide valuable insights into phenomena such as developmental plasticity, epigenetic regulation, and adaptive responses to environmental stress. Symbiotic relationships in Stilbonematinae and Astomonematinae, alongside the antimicrobial properties of the Oncholaimidae species, offer unique opportunities to explore mutualistic evolution and resilience in extreme environments. Despite challenges in culturing these species, recent advances in culturing other meiofaunal organisms with chemosynthetic symbionts have opened up promising opportunities. The roles of marine nematodes as ethical and versatile models position them to address pressing challenges in biological and biomedical research, highlighting their significant potential for future studies.

Seamounts are prominent volcanic seafloor features whose morphology affects many ocean processes, sustaining deep-sea communities and providing many ecosystem functions and services. Their study contributes to the understanding of many geological, oceanographic, biological, and ecological processes. Despite their acknowledged vulnerability to human activities and climate change, the recovery time and ecological implications need to be properly understood. Moreover, only recently conservation measures have been considered. In this study, a bibliometric analysis of the scientific literature related to seamounts and their conservation was conducted. The analysis allowed for the generation of network maps displaying the relationships among keywords and countries. A total of 8019 articles were found regarding seamounts, 332 of which were related to their conservation. The results show that the main research fields concerned with seamounts are geology, seismology, geochemistry, oceanography, and biodiversity, whereas those regarding their conservation are corals, marine protected areas, benthos, community structure, fisheries, and management measures. Scientific papers about seamounts were published by 191 authors across 50 countries, while 19 authors across 25 countries published about their conservation. This study highlights the necessity to expand scientific knowledge on seamounts, especially regarding their ecological processes, to provide useful data for the successful management and conservation of these still mostly unexplored habitats.