1,721,064 research outputs found
Ecology and diversity of Mediterranean hard-bottom Syllidae (Annelida): A community-level approach
Full text linkThe Syllidae are geographically widespread polychaetes, particularly diverse and abundant on marine hard bottoms and in seagrass meadows. Hydrodynamics, habitat complexity and biological traits are hypothesized to influence syllid bathymetric distribution. Little is known about the consistency of, or variation in, horizontal distribution patterns with varying depth. I analyzed hard-bottom Syllidae at 2 depths (1.5 and 5 m) at the scale of 1000s of metres, located around the Torre Guaceto marine protected area (MPA) (SE Italy) in order to (1) quantify syllid diversity and abundance, (2) describe their distribution pattern and (3) identify potentially important factors influencing their distribution. The Syllidae were dominant and highly diverse, and new bio - geographic records were reported. Horizontal distribution patterns changed with depth, being more variable at 1.5 than 5 m. The presence of the MPA had little effect on alongshore variation in individual species abundance and assemblage structure. Contrary to expectations, there was no consistent relationship between Syllidae distribution and habitat-forming algal species. In contrast, syllid abundance varied with that of other invertebrates, suggesting that future research should focus on the role of interspecific interactions in syllid ecology. Syllidae are a highly diversified and widespread taxon that deserves special attention when analyzing biodiversity patterns of hard-bottom benthic communities. © Inter-Research 2012 · www.int-res.com
Faunal and biogeographic analysis of Syllidae (Polychaeta) from Rovinj (Croatia, northern Adriatic Sea)
Full text linkThe study of hard-bottom Syllidae (Polychaeta) of the Rovinj area provides an updated measure of syllid species diversity in the northern Adriatic Sea. Faunal research in the coldest Mediterranean sectors may also help to address possible ecological and biogeographical consequences arising from climate change. Thirty-nine species were found, of which 13 are new for the northern Adriatic, increasing the species recorded from the area from 53 to 66. Some newly recorded species are dominant and typical of warmer areas. The lack of previous taxonomic updates is responsible for the high number of new findings. However, the northern Adriatic Sea is possibly undergoing long-term changes, with modifications of diversity due to the establishment of warm-water species. Syllid fauna of Sveti Ivan Island and its bioclimatic affinity are, in fact, unexpectedly more similar to the ones of some southern Mediterranean areas than to those traditionally reported for the northern Adriatic
A new species of sphaerosyllis (polychaeta, syllidae, exogoninae) from the coasts of italy and cyprus (eastern mediterranean sea)
No full textThe faunistic analysis of hard and soft benthic materials collected from the Marine Reserve of Porto Cesareo (Ionian Sea, Salento Peninsula, Italy) and the coast of northern Cyprus (Levant Sea) revealed a new species of Sphaerosyllis, S. boeroi sp. n. (Polychaeta, Syllidae, Exogoninae). This species is mainly characterized by having compound chaetae with discernable subdistal spine, a strong dorso-ventral gradation in size of blades throughout the body, elongated slender blades of superior compound chaetae on anterior and middle parapodia, parapodial glands with fibrillar material, and the distributional pattern of papillae on the body surface. Sphaerosyllis boeroi is described and compared to the other morphologically similar species, with emphasis on its ecological and reproductive patterns. © 2005 Taylor & Francis Group, LLC.Two of the Authors (L.M. and A.G.) wish to thank Drs Caterina Longo, Mariella Mercurio and Carlotta Nonnis Marzano from the University of Bari, and Dr. Cataldo Pierri from the University of Lecce for their help during the sampling phase. The other Author (M.E.Ç.) also thanks the crews and scientific personnel of the R/V K. PIRI REIS for their help in obtaining benthic samples, and TUBITAK (NATO-B1 Programme) for the financial support that enabled him to visit some research stations in Italy to make this collaboration possible. -
Cohabiting with litter: Fish and benthic assemblages in coastal habitats of a heavily urbanized area
No full textAnthropogenic litter negatively impacts the marine environment and threatens biodiversity. At the same time, it represents a suitable substrate for the settlement of sessile species, thus potentially altering composition and structure of soft bottom benthic assemblages. By using a Remotely Operated Vehicle (ROV), we hereby investigated patterns of abundance, distribution, and origin of benthic litter in three subtidal habitats of a heavily urbanized area and tested whether litter distribution related to patterns of fish and mega- and macro-benthic diversity. Litter accumulation mostly occurred on soft bottoms, while rocky substrata were the least affected, albeit being particularly threatened by sea-based pollution. As expected, the highest biodiversity was observed on rocky bottoms, hosting notable biogenic formations (Cladocora caespitosa, Leptogorgia sarmentosa) despite the area is historically affected by anthropogenic activities. No correlation was found between biota and marine litter, suggesting that litter does not apparently influence biodiversity and distribution of the investigated assemblages
Crostacei Anfipodi associati ai reef di Sabellaria alveolata (Annelida: Sabellariidae) del Canale di Sicilia (Mar Mediterraneo)
No full textWe describe diversity and patterns of spatial distribution of the amphipod fauna associated
with reefs of the polychaete Sabellaria alveolata (L.) in the Sicily Strait. Samples were collected in
June 2013, at three localities. Amphipod assemblages appeared homogeneous in the study area with
variability increasing with decreasing spatial scale of observation. Jassa ocia (Bate) and Gammaropsis
ulrici Krapp-Schickel & Myers characterized the studied assemblages
Behavioural responses of the colonial sea squirt botrylloides violaceus oka to suspended food micro‐ particles in laboratory cultures
Full text linkViolet sea squirts are noteworthy model organisms, because they provide insights into various physiologic processes, including cell senescence, ageing, apoptosis and allorecognition. Consequently, their culture is critical to permit experimental studies. Most papers refer to short periods of rearing using various feeds, both living and conserved, missing a formal justification for their use or indications of their actual nutritional value. Here, we use two behavioural responses— the percentage of open siphons and the frequency of zooid contractions—as compared to the abundance of suspended microparticles during feeding tests, to identify feeds able to promote filter-feeding. The results will enable to formulate compound diets that maximise positive physiological responses. Our tests demonstrated that plant items, such as dry microalgae and cyanobacteria (Arthrospira platensis, commercially known as Spirulina), along with living planktonic Haptophyta (Isochrysis galbana), trigger clear positive reactions, represented by a higher frequency of zooid contractions and larger proportions of open siphons. These responses correspond to decreases in the concentrations of suspended microparticles during the experiment and indicate higher filter-feeding activity. In contrast, feeds commonly administered to colonies, such as milk powder, dried eggs and artificial plankton, triggered negative behavioural responses, and their intake was lower during the feeding trials
A new sponge-associated species, Syllis mayeri n. sp (Polychaeta : Syllidae), with a discussion on the status of S-armillaris (Muller, 1776)
Full text linkIn the framework of a study carried Out along the Belizean coasts, a new species of syllid. Syllis mayeri n. sp.. was found harboured by the sponge Ircinia strobilina. The description of this new taxon is given.. and compared to other similar congeneric species and to some Mediterranean material from the Southern Italian coast ascribed to S. armillaris. The new species is characterized by some stout compound chaetae with ypsiloid appearance, whose probable use for attaching to the host is hypothesized. Other diagnostic features are antennae, tentacular cirri and dorsal cirri of the anterior portion of the body that are longer than in similar, compared species. Moreover, the mid-body dorsal cirri are typically spindle-shaped. A discussion on the status of some sponge-associated taxa from tropical and Subtropical seas attributed to the so-called cosmopolitan S. armillaris is also give
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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