Field evidence for microplastic interactions in marine benthic invertebrates

Microplastics represent an important issue of concern for marine ecosystems worldwide, and closed seas, such as the Mediterranean, are among the most affected by this increasing threat. These pollutants accumulate in large quantities in benthic environments causing detrimental effects on diverse biocenoses. The main focus of this study is on the ‘polychaetes-microplastics’ interactions, particularly on two species of benthic polychaetes with different ecology and feeding strategies: the sessile and filter feeder Sabella spallanzanii (Gmelin, 1791) and the vagile carnivorous Hermodice carunculata (Pallas, 1766). Since not standardized protocols are proposed in literature to date, we compared efficiencies of diverse common procedures suitable for digesting organic matter of polychaetes. After the definition of an efficient digestion protocol for microplastics extraction for both polychaetes, our results showed high microplastics ingestion in both species. Microplastics were found in 42% of individuals of S. spallanzanii, with a mean of 1 (± 1.62) microplastics per individual, in almost all individuals of H. carunculata (93%), with a mean of 3.35 (± 2.60). These significant differences emerged between S. spallanzanii and H. carunculata, is probably due to the diverse feeding strategies. The susceptibility to this pollutant makes these species good bioindicators of the impact of microplastics on biota.

A Minireview on Biodiscovery in Antarctic Marine Benthic Invertebrates

Antarctic marine benthic invertebrates are an underexplored source of natural products for biodiscovery. Bioactive marine natural products from Antarctica are reviewed here for their potential use as drugs, considering the main examples in Porifera (15 species), Cnidaria (eight species), Mollusca (one species), Bryozoa (one species), Nemertea (one species), Echinodermata (six species), and Tunicata (five species). A wide variety of bioactivities are reported here, from antitumoral to antimicrobial activities, as well as against neurodegenerative diseases and others. If we aim to use their chemodiversity for human benefits we must maintain the biodiversity, solving the supply problem, speeding up the process, and decreasing research costs to fully exploit the benefits of biodiscovery in Antarctic Marine Natural Products in a near future in a sustainable way.

In situ microplastics ingestion by Antarctic marine benthic invertebrates

<p>Microplastics have been recognised as persistent marine contaminants and mounting evidence supports their designation as anthropogenic stressors to marine organisms. Despite the remoteness of Antarctica, microplastics contamination has been reported in every marine environment investigated in this area to date. Due to ocean currents and frontal systems, microplastics may become entrapped within polar regions and increase bioavailibilty to inhabiting fauna. Antarctic marine benthic invertebrates represent a research priority due to their sensitivity to change as well as contribution to ecological functioning and food webs. The current study investigated microplastics ingestion by the epifaunal, carnivorous polychaete <em>Barrukia cristata</em> and the infaunal, filter-feeding bivalve, <em>Laternula elliptica</em>. Animals were collected by SCUBA adjacent to Rothera research station, Adelaide Island. After digestion in 10 % potassium hydroxide (KOH) followed by filtration, microplastics ingested by individual animals were separated. Microplastics were then counted and characterised by shape, colour, size and polymer type by Micro-Fourier transform Infrared spectroscopy. Polyethylene terephthalate (PET) was the most abundant polymer type, followed by polyacrylonitrile (PAN) and ethylene-vinyl acetate (EVA). Congruent to earlier reports, fibres were found to be the most abundant source of microplastics contamination. However, it must be highlighted that fragments were also recovered from the animals analysed. Results determined the current level of microplastics ingestion by two benthic marine invertebrates of different feeding strategies in coastal environments of the Antarctic Peninsula. These findings indicated the bioavailability of microplastics and highlighted the potential of trophic transfer throughout the Antarctic marine food web.</p>

Phanerozoic variation in dolomite abundance linked to oceanic anoxia

The abundance of dolomitic strata in the geological record contrasts with the general rarity of locations where dolomite forms today, a discrepancy that has long posed a problem for their interpretation. Recent culture experiments show that dolomite can precipitate at room temperature, raising the possibility that many ancient dolomites may be of syngenetic origin. We compiled a large geodata set of secular variations in dolomite abundance in the Phanerozoic, coupled with compilations of genus richness of marine benthic invertebrates and sulfur-isotope variations in marine carbonates. These data show that dolomite abundance is negatively correlated to genus diversity, with four dolomite peaks occurring during mass extinctions. Dolomite peaks also correspond to the rapid increase in sulfur-isotope composition (δ34S), an indicator of enhanced sulfate reduction, in anoxic oceans. These results confirm that variations in dolomite abundance during the Phanerozoic were closely linked with changes in marine benthic diversity, with both in turn related to oceanic redox conditions.

Discovery of the female of Cymbasoma rochai Suárez-Morales & Dias, 2001 (Copepoda, Monstrilloida, Monstrillidae), the first Brazilian member of the C. longispinosum species-group

Monstrilloid copepods are protelean parasites of marine benthic invertebrates; their juvenile stages are entirely endoparasitic and emerge from the host as free-living reproductive adult individuals that become part of the plankton. Linking both sexes of a monstrillid species is difficult because individuals of both sexes and members of different species can be collected together as planktonic adults. The Brazilian species Cymbasoma rochai Suárez-Morales & Dias, 2001, known from male specimens only, was recognized to have a strong resemblance to the nominal C. longispinosum, currently recognized as a well-defined species-group (Suárez-Morales, 2011). Hence, it was expectable that the female C. rochai would also resemble the species of the C. longispinosum species-group. Plankton surveys in Brazilian coastal areas yielded records of several female individuals reported as Cymbasoma cf. longispinosum. It is presumed that these are the females of C. rochai. The hitherto unknown female of C. rochai is herein described as such, and in addition revealed and described as a member of the widespread C. longispinosum species-group, now containing 11 species worldwide. This is the first confirmed record of a member of this group from Brazil and also the first known male of this species-group.

Survive or swim: different relationships between migration potential and larval size in three sympatric Mediterranean octocorals

Knowledge about migration potential is key to forecasting species distributions in changing environments. For many marine benthic invertebrates, migration happens during reproduction because of larval dispersal. The present study aims to test whether larval size can be used as a surrogate for migration potential arising from larval longevity, competence, sinking, or swimming behavior. The hypothesis was tested using larvae of three sympatric gorgonian species that release brooded lecithotrophic larvae in the same season: Paramuricea clavata, Corallium rubrum and Eunicella singularis. Despite different fecundities and larval sizes, the median larval longevity was similar among the three species. Free-fall speed increased with larval size. Nevertheless, the only net sinkers were the P. clavata larvae, as swimming was more common than free fall in the other two species with larger larvae. For the other two species, swimming activity frequency decreased as larval size increased. Interestingly, maximum larval longevity was lowest for the most active but intermediately sized larvae. Larval size did not covary consistently with any larval traits of the three species when considered individually. We thus advise not using larval size as a surrogate for migration potential in distribution models. The three species exemplified that different mechanisms, i.e., swimming activity or larval longevity, resulting from a trade-off in the use of energy reserves can facilitate migration, regardless of life history strategy.