Short communication: The hidden invasion of the alien seagrass Halophila stipulacea (Forsskål) Ascherson along Southeastern Italy

The seagrass Halophila stipulacea (Forsskål) Ascherson (Hydrocharitaceae) is a non-indigenous species (NIS) for the Mediterranean Sea. This species is expected to have a high potential for invasiveness based on models predicting the present and future suitability of the Mediterranean coasts with respect to the plant requirements. This species was recorded for the first time along the Apulian coast in the Otranto harbor in 2011. Such a record was not considered in recent publications dealing with the species distribution and its forecasted invasion pathway, probably due to the scant information provided. One decade after its first record in the area, we confirmed the presence of the H. stipulacea meadow in the same locality (Otranto), and we identified four new H. stipulacea meadows along the Ionian coast are between 1 and 30 m deep in touristic areas. Indirect evidence suggests that the plant is actively spreading along the southeastern Italian coast, and monitoring programs aiming at mapping its distribution in the area, as well as its potential effect on the native biota, are required

Diversity and Distribution of Sabellida (Annelida) under Protection Regimes

Sabellida are widespread, diverse and abundant in marine benthic habitats. Their distribution patterns on hard-bottom substrates are poorly studied so far. Little is known about the factors influencing their distribution, including the protection regimes that are known to affect assemblage diversity. We analyzed hard-bottom Sabellida at 1.5 and 5 m depths at the Torre Guaceto Marine Protected Area (MPA) (SE Italy) to describe diversity and distribution patterns, and to identify potential factors influencing their distribution. The Sabellida diversity varied significantly among stations and was higher at 5 m depth. No relation with the protection regime was found. Among environmental variables, only sedimentation appeared related, suggesting that local trophic features might have influenced the observed pattern. Among habitat formers, only the macroalga Halimeda tuna significantly explained part of the observed variation, probably due to its role as a basibiont for some Sabellida taxa. Other predictor variables of Sabellida distribution were the abundances of some invertebrate taxa, especially Syllidae and some filter feeders such as Sabellariida and Cirripedia, probably due to shared ecological requirements, rather than a direct effect on Sabellida distribution. The relation with the Syllidae remains obscure so far, albeit some kind of interaction (including predator/prey interactions) between these two taxa cannot be excluded. Sabellida should be taken into account when analyzing patterns of biodiversity of hard-bottom environments

I sillidi (Annelida, Polychaeta) del litorale brindisino: possibilità di un loro impiego come indicatori di qualità dell\'ambiente

EnThe biodiversity of Syllidae (Annelida, Polychaeta) was examined along the Brindisi coast (Adriatic Sea), an area previously poorly known concerning the Polychaete syntaxon. The finding of 5 species new for the Italian coast was enhanced.Sample period relative to the construction of Cerano power-station, allowed to point out some important changes within syllid assemblages, both in species composition and abundance. These changes were observed proceeding from the Southern area of Cerano to the Northern one. This orizontal gradient overlapped to the "normal" batimetric gradient. Syllid species seem to respond to disturbance in a very short time, thus leading to consider the group as indicative of environmental quality

Il Macrozoobenthos

EnMacrobenthic samples were collected in 4 sites inside the Acquatina lake (3 replicates for each site in two times: July 2006 and January 2007). A total of 5029 individuals belonging to 50 taxa were found, with molluscs taxonomically dominant (26 taxa), followed by polychaetes (19 taxa), which was instead numerically dominant due to the massive presence of the species Heteromastus filiformis. Data were analysed by multivariate techniques. The assemblage was quite homogeneous within the lake, with more quantitative than qualitative differences among sites. Statistical analysis showed two sites, representing the two extreme of the biotope condition, as the most variable ones and separated from the others, located in the middle of the investigated biotope. The separation of the two sites from this central more homogeneous area was due to a different distribution between molluscs and polychaetes species. The comparison of the polychaete distribution between data relative to a previous period of study and present ones revealed a more diversified assemblage, with the disappearance of some opportunistic forms, and with an homogenization within the basin, underlining the disappearance of the strong salinity gradient

Sperm ultra-structure and spermiogenesis in <i>Syllis krohni</i> (Polychaeta: Syllidae), with some observations on its reproductive biology

yllidae show a wide spectrum of both reproductive strategies and sperm types. Analysis of their reproductive patterns could drastically change the presently accepted taxonomic hierarchy of the group. To further contribute to the knowledge of Syllidae we have described the sperm ultra-structure and the spermiogenesis of Syllis krohni (Ehlers, 1864). Mature sperm has a cone-shaped acrosome whose distal end is notched by a trough that transversely encircles its anterior portion. During spermiogenesis, the acrosomal vesicle undergoes modifications leading to its final shape with a posterior opening. The nucleus appears flattened anteriorly and forms a cleft that surrounds the proximal centriole in its distal region. A 9+2 flagellar axoneme is observed. Up to five mitochondria surround the distal centriole. The spermatozoon of S. krohni can be ascribed to the ect-aquasperm type that is typical in species having external fertilisation and appears to be very similar in appearance to that of the congeneric species thus far investigated. The main difference is in the shape of the acrosome, which is more elongated and as long as the nucleus. Reproduction of syllids seems to be conservative within sub-families, and the sperm morphology can probably help in phylogenetic reconstruction. External fertilisation is a widespread strategy within the genus Syllis, probably leading to a substantial similarity in sperm morphology being maintained. It is hypothesised, however, that within the same sperm type linked to a particularly reproductive strategy, the acrosome ultra-structure can be indicative of phylogeny

A Bioinspired Fluid-Filled Soft Linear Actuator

In bioinspired soft robotics, very few studies have focused on fluidic transmissions and there is an urgent need for translating fluidic concepts into realizable fluidic components to be applied in different fields. Nature has often offered an inspiring reference to design new efficient devices. Inspired by the working principle of a marine worm, the sipunculid species Phascolosoma stephensoni (Sipunculidae, Annelida), a soft linear fluidic actuator is here presented. The natural hydrostatic skeleton combined with muscle activity enables these organisms to protrude a part of their body to explore the surrounding. Looking at the hydrostatic skeleton and protrusion mechanism of sipunculids, our solution is based on a twofold fluidic component, exploiting the advantages of both pneumatic and hydraulic actuations and providing a novel fluidic transmission mechanism. The inflation of a soft pneumatic chamber is associated with the stretch of an inner hydraulic chamber due to the incompressibility of the liquid. Actuator stretch and forces have been characterized to determine system performance. In addition, an analytical model has been derived to relate the stretch ability to the inlet pressure. Three different sizes of prototypes were tested to evaluate the suitability of the proposed design for miniaturization. The proposed actuator features a strain equal to 40–50% of its initial length—depending on size—and output forces up to 18 N in the largest prototypes. The proposed bioinspired actuator expands the design of fluidic actuators and can pave the way for new approaches in soft robotics with potential application in the medical field

A Comparative Approach to Detect Macrobenthic Response to the Conversion of an Inshore Mariculture Plant into an IMTA System in the Mar Grande of Taranto (Mediterranean Sea, Italy)

The expected bioremediation effect, driven by the conversion of an inshore mariculture plant into an Integrated Multi-Trophic Aquaculture (IMTA) system, which could mitigate the fish farm impact, related to the accumulation of organic matter on the seabed, has been studied. The ecological quality status was studied following a Before-After-Control-Impact (BACI) design and variation measured through M-AMBI and compared with the results of univariate and multivariate analyses of variance, to evaluate the sensitivity of the two methodologies. Results from M-AMBI indicated a sharp change in the ecological quality status, just after one year of the conversion of the plant. By contrast, although changes were detected also utilizing univariate and multivariate statistical analysis, the natural temporal variability characterizing the area partially masked evidence of environmental amelioration

Hard-Bottom Polychaetes Exposed to Multiple Human Pressure along the Mediterranean Coast of Egypt

The complex mixture of anthropogenic pressure determines the impact on the marine biota, hampering the ecosystem's functioning. The coast of Alexandria, Egypt, experiences multiple human pressure, including sewage discharge, engineering activities (urbanization) for armoring purposes, and beach nourishment. Hard-bottom polychaete assemblages are demonstrated to reflect coastal areas' environmental status, though their use in monitoring programs is uncommon. The sensitivity of hard-bottom polychaete assemblages in depicting variations in environmental conditions of two sites exposed to the discharge of polluted water and three sites exposed to urbanization was analyzed. The high spatial and temporal variation in species abundance and diversity probably hid differences among the assemblages exposed to the two forms of pressure while highlighting differences among sites exposed to the same impact form. In addition, changes in the algal substrate probably influenced the observed pattern. Temporal variation of salinity and differences in biological oxygen demand (BOD) and the organic matter appeared to indirectly affect polychaete abundance and diversity by favoring tolerant algal taxa such as Ulva sp. Contrary to what was expected, assemblage variation due to site-specific environmental features accounted for more than the variations due to the two forms of human pressure in shaping differences among polychaete assemblages