Contribution of soft-bodied meiofaunal taxa to Italian marine biodiversity

Trophic organization of the benthic communities off the South Italian coasts: A review with a modelistic approach

Limited data are available about the coastal ecology of the Calabria region, in the southern Italy. As well, data about the levels of biodiversity and the structure of food webs in these environments are totally missing. However, considering the wide range of physical and ecological conditions distinguishing these ecosystems, a remarkable spread of biodiversity is expected. This review represents a first attempt to describe and estimate the structure of the food webs in a range of shallow stations along the south-western coasts of southern Italy, in the Ionian Sea. They comprise a Special Area of Conservation (Amendolara shoal), an urbanized area (Sibari), a sandy area impacted by industrial installations (Corigliano) and a seagrass meadow (Calopezzati). For each of these stations, we produced ecological simulation models based on the available information in order to estimate the structure of food webs. In particular, the patterns of distribution of trophic resources resulting from literature data were statistically compared to a theoretical model based on the physical and ecological features of coastal ecosystems. The model was responsive and predicted remarkable differences in the compartmentalization of trophic resources among stations, due to the diversity of substrates and the anthropic activities impacting each area. Large availability of resources for omnivores and detritivores characterized most stations. A noteworthy richness of trophic resources for herbivores was forecasted off Amendolara and Calopezzati. In parallel, the model obtained for the urbanized area of Sibari predicted a higher abundance of trophic resources for filter feeders, especially in the deepest station.

First record of a proseriate flatworm predating on a rhabdocoel (Platyhelminthes: Proseriata and Rhabdocoela)

Microturbellarian flatworms comprise a diverse assemblage amongst meiofauna. These animals primarily exhibit carnivorous feeding habits, preying on various organisms, such as crustaceans, annelids and even other microturbellarians. However, details of their diet are poorly known. This study represents the first documentation of a proseriate preying upon a rhabdocoel. The proseriate was extracted from the sediment and studied alive. Within its digestive tract, structures of the reproductive systems of its prey were observed and identified as belonging to Phonorhynchopsishaegheni, a predatory turbellarian as well. No remains of any other organisms were detected. This finding underscores the relevance of Proseriata as top-level predators within the meiofaunal trophic web, a role that warrants further consideration beyond what has been previously acknowledged.

First trait-based characterization of Arctic ice meiofauna taxa

Trait-based approaches connect the traits of species to ecosystem functions to estimate the functional diversity of communities and how they may respond to environmental change. For the first time, we compiled a traits matrix across 11 traits for 28 species of Arctic ice meiofauna, including Copepoda (Subclass), Nematoda (Phylum), Acoela (Order), Rotifera (Phylum), and Cnidaria (Phylum). Over 50 years of pan-Arctic literature were manually reviewed, and trait categories were assigned to enable future trait–function connections within the threatened ice-associated ecosystem. Approximately two-thirds of the traits data were found at the genus or species level, ranging from 44% for Nematoda to 100% for Cnidaria. Ice meiofauna were shown to possess advantageous adaptations to the brine channel network within sea ice, including a majority with small body widths < 200 μm, high body flexibility, and high temperature and salinity tolerance. Diets were found to be diverse outside of the algal bloom season, with most organisms transitioning to ciliate-, omnivore-, or detritus-based diets. Eight species of the studied taxa have only been recorded within sea ice, while the rest are found in a mixture of sympagic–pelagic–benthic habitats. Twelve of the ice meiofauna species have been found with all life stages present in sea ice. Body width, temperature tolerance, and salinity tolerance were identified as traits with the largest research gaps and suffered from low-resolution taxonomic data. Overall, the compiled data show the degree to which ice meiofauna are adapted to spending all or portions of their lives within the ice.