The BenBioDen database, a global database for meio-, macro- and megabenthic biomass and densities.

Benthic fauna refers to all fauna that live in or on the seafloor, which researchers typically divide into size classes meiobenthos (32/64 µm-0.5/1 mm), macrobenthos (250 µm-1 cm), and megabenthos (>1 cm). Benthic fauna play important roles in bioturbation activity, mineralization of organic matter, and in marine food webs. Evaluating their role in these ecosystem functions requires knowledge of their global distribution and biomass. We therefore established the BenBioDen database, the largest open-access database for marine benthic biomass and density data compiled so far. In total, it includes 11,792 georeferenced benthic biomass and 51,559 benthic density records from 384 and 600 studies, respectively. We selected all references following the procedure for systematic reviews and meta-analyses, and report biomass records as grams of wet mass, dry mass, or ash-free dry mass, or carbon per m2 and as abundance records as individuals per m2. This database provides a point of reference for future studies on the distribution and biomass of benthic fauna.

Molecular phylogeny, morphology, and distribution of Polygordius (Polychaeta: Polygordiidae) in the Atlantic and Mediterranean.

Low morphological diversity among interstitial taxa makes it difficult to delimit species and their geographic boundaries based solely on morphology and molecular data often reveal cryptic species. Polygordius (Annelida, Polygordiidae) have low morphological diversity, but are unusual among interstitial species in their comparatively large size due to their elongated form, high fecundity, and potential for long-distance dispersal via a planktotrophic larval stage. Polygordius species collected from 14 localities in the Northwest Atlantic, Mediterranean Sea, and Southwest Atlantic including several of the respective type localities were analysed. This study presents the first phylogeny of the genus Polygordius and combines molecular data, sequences of COI, 16S and ITS1/2 genes, and morphological data for a systematic re-evaluation focusing on Atlantic species, with an emphasis on populations from European waters. Phylogenetic analyses recovered six valid species (P. appendiculatus, P. lacteus, P. neapolitanus, P. triestinus, P. jouinae, and P. eschaturus) and their distinctness is confirmed by haplotype network analyses. Thus, molecular data supported the validity of the previously recognized morpho-species and no new species were present. P. erythrophthalmus and P. villoti are invalid species being synonymous with P. lacteus. Subtle differences in head and pygidial morphology and larval type (endolarva vs. exolarva), were useful characters for discrimination. Yet seemingly significant variation in characters among individuals in some species was not diagnostic (e.g., number of pygidial cirri). Highly similar species based on adult morphology were shown to be sister taxa occurring in allopatry. Present day distribution patterns of species are summarized in light of this study.

Spontaneous alternation and locomotor activity in three species of marine crabs: green crab (Carcinus maenas), blue crab (Callinectes sapidus), and fiddler crab (Uca pugnax).

Spontaneous alternation refers to the tendency of organisms to explore places that they have least recently visited. Our previous work showed that alternation performance of Carcinus maenas (invasive European green crab) was significantly higher than Callinectes sapidus (native blue crab), and chance level performance (Ramey, P. A., Teichman, E., Oleksiak, J., & Balci, F. [2009]. Spontaneous alternation in marine crabs: Invasive versus native species. Behavioural Processes, 82, 51-55.). In the current study, we first tested the robustness of these findings in the absence of visual cues, longer test durations, and wider maze dimensions. These manipulations enabled us to determine whether these two crab species relied on the visual cues provided during the spontaneous alternation task in our prior work, and allowed for better characterization of their exploratory activity in the maze. Our original findings were reproduced in the present study under these new task conditions, suggesting no role for visual cues during alternation, and emphasizing the robustness and generalizability of the corresponding interspecies differences in alternation performance. We also tested whether the lower alternation performance of C. sapidus also applied to another native crab species, Uca pugnax (fiddler crab). Spontaneous alternation performance of U. pugnax was significantly lower than C. maenas but indistinguishable from C. sapidus. Finally, we examined whether the potentially higher inherent risk-sensitivity of C. sapidus could have contributed to their lower alternation performance by testing C. maenas in the presence of a larger natural predator (stressor). Higher risk sensitivity presumably induced by the stressor led to locomotor activity patterns that better resembled those of C. sapidus, however the resultant reduction in alternation performance was not statistically significant.