The amphipod assemblages of Sabellaria alveolata reefs from the NW coast of Portugal: An account of the present knowledge, new records, and some biogeographic considerations

Amphipod assemblages associated with the biogenic reefs built by the honeycomb worm Sabellaria alveolata were studied at two sites (Praia da Aguda and Belinho) along the northwestern coast of Portugal. A total of 3909 specimens were collected, comprising 14 different amphipod species. A first record from the northeastern Atlantic coast was registered here for the species Caprella santosrosai, which was, up to now, recorded only along the Mediterranean coast of the Iberian Peninsula. A male specimen collected from the Sabellaria-reef located in Belinho allowed an update to the known distribution of C. santosrosai, thus altering its previous status as an endemic Mediterranean species. The most common species collected during the study were Microdeutopus chelifer (n = 1828), Jassa ocia (n = 1426), and Hyale stebbingi (n = 452). Forty-three percent of the total recorded species were encountered in both study sites, whereas the remaining 57 % were restricted to a single site (Belinho). The majority of the collected species (93 %) showed an Atlantic-Mediterranean distribution, confirming the close affinity between eastern Atlantic and Mediterranean amphipod assemblages and the role of the Portuguese coast as a transition zone through which numerous warm-water species, coming from North Africa and the Mediterranean Sea, could enter into the Atlantic and possibly get mixed with species coming from the North Sea and the Arctic, typically having affinity for colder waters

First assessment of plasticizers in marine coastal litter-feeder fauna in the mediterranean sea

Micro and nanoplastics are harmful to marine life due to their high level of fragmentation and resistance to degradation. Over the past two decades, marine coastal sediment has shown an increasing amount of microplastics being a sort of trap for debris wastes or chemicals. In such an environment some species may be successful candidates to be used as monitors of environmental and health hazards and can be considered a mirror of threats of natural habitats. Such species play a key role in the food web of littoral systems since they are litter-feeders, and are prey for fishes or higher trophic level species. A preliminary investigation was conducted on five species of small-sized amphipod crustaceans, with the aim to understand if such an animal group may reflect the risk to ecosystems health in the central Mediterranean area, recently investigated for seawater and fish contamination. This study intended to gather data related to the accumulation of plasticizers in such coast dwelling fauna. In order to detect the possible presence of xenobiotics in amphipods, six analytes were scored (phthalic acid esters and non-phthalate plasticizers), identified and quantified by the gas chromatography mass spectrometry (GC-MS) method. The results showed that among all the monitored contaminants, DEP and DiBP represented the most abundant compounds in the selected amphipods. The amphipod crustaceans analyzed were a good tool to detect and monitor plasticizers, and further studies of these invertebrates will help in developing a more comprehensive knowledge of chemicals spreading over a geographical area. The results are herein presented as a starting point to develop baseline data of plasticizer pollution in the Mediterranean Sea

Assessment of the Sabellaria alveolata reefs’ structural features along the Southern coast of Sicily (Strait of Sicily, Mediterranean Sea)

The honeycomb worm Sabellaria alveolata is a gregarious tube-dwelling polychaete that builds remarkable biogenic reefs in marine coastal waters. Sabellaria alveolata reefs are considered valuable marine habitats requiring protection measures for their conservation, as they play a key role in the functioning of coastal ecosystems. Sabellarid reefs are extensively developed along the Atlantic coasts of Europe and reported for the Mediterranean Sea and the Italian coasts, where large reefs have been recorded in several localities. Fragmentary information is available on their health status, Sabellaria reefs thus being listed as “Data Deficient” in the Red List of Marine Habitats. To fill this knowledge gap, this study focused on the analysis of the structure of three reefs found along the southern coast of Sicily. In particular, we aimed to assess their phases with respect to the natural cycle that characterizes the sabellarid reefs. Reef features were analyzed both on the macroscale, based on the bioconstruction size (diameter and thickness) and degree of fragmentation, and on the microscale, based on the measurement of worm density, opercular length and sand porch presence. This study reveals relevant differences among reefs of the studied locations. These differences we attribute to the temporal shift linked to the natural reef phases, albeit further analyses are needed to understand the possible effect of natural and anthropogenic sources of variation on the Southern Sicilian reefs. In conclusion, Sabellaria reefs are a unique and persistent habitat along the Sicilian coast requiring proper management and conservation measures

Steps towards the hyperfine splitting measurement of the muonic hydrogen ground state: pulsed muon beam and detection system characterization

The high precision measurement of the hyperfine splitting of the muonic-hydrogen atom ground state with pulsed and intense muon beam requires careful technological choices both in the construction of a gas target and of the detectors. In June 2014, the pressurized gas target of the FAMU experiment was exposed to the low energy pulsed muon beam at the RIKEN RAL muon facility. The objectives of the test were the characterization of the target, the hodoscope and the X-ray detectors. The apparatus consisted of a beam hodoscope and X-rays detectors made with high purity Germanium and Lanthanum Bromide crystals. In this paper the experimental setup is described and the results of the detector characterization are presented.Comment: 22 pages, 14 figures, published and open access on JINS

MICE: the Muon Ionization Cooling Experiment. Step I: First Measurement of Emittance with Particle Physics Detectors

The Muon Ionization Cooling Experiment (MICE) is a strategic R&D project intended to demonstrate the only practical solution to providing high brilliance beams necessary for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (RAL) in the United Kingdom. It comprises a dedicated beamline to generate a range of input muon emittances and momenta, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam will be measured in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in Liquid Hydrogen (LH2) absorbers to RF cavity acceleration. A second spectrometer, identical to the first, and a second muon identification system will measure the outgoing emittance. In the 2010 run at RAL the muon beamline and most detectors were fully commissioned and a first measurement of the emittance of the muon beam with particle physics (time-of-flight) detectors was performed. The analysis of these data was recently completed and is discussed in this paper. Future steps for MICE, where beam emittance and emittance reduction (cooling) are to be measured with greater accuracy, are also presented

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2–2.3 π mm-rad horizontally and 0.6–1.0 π mm-rad vertically, a horizontal dispersion of 90–190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE

MICE: The muon ionization cooling experiment. Step I: First measurement of emittance with particle physics detectors

Copyright @ 2011 APSThe Muon Ionization Cooling Experiment (MICE) is a strategic R&D project intended to demonstrate the only practical solution to providing high brilliance beams necessary for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (RAL) in the United Kingdom. It comprises a dedicated beamline to generate a range of input muon emittances and momenta, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam will be measured in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in Liquid Hydrogen (LH2) absorbers to RF cavity acceleration. A second spectrometer, identical to the first, and a second muon identification system will measure the outgoing emittance. In the 2010 run at RAL the muon beamline and most detectors were fully commissioned and a first measurement of the emittance of the muon beam with particle physics (time-of-flight) detectors was performed. The analysis of these data was recently completed and is discussed in this paper. Future steps for MICE, where beam emittance and emittance reduction (cooling) are to be measured with greater accuracy, are also presented.This work was supported by NSF grant PHY-0842798

The FAMU experiment at RIKEN-RAL to study the muon transfer rate from hydrogen to other gases

The aim of the FAMU (Fisica degli Atomi Muonici) experiment is to realize the first measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen _Ehf s 1S , by using the RIKEN-RAL intense pulsed muon beam and a high-energy mid-infrared tunable laser. This requires a detailed study of the muon transfer mechanism at different temperatures and hence at different epithermal states of the muonic system. The experimental setup involves a cryogenic pressurized gas target and a detection system based on silicon photomultipliers-fiber beam hodoscopes and high purity Germanium detectors and Cerium doped Lanthanium Bromide crystals, for X-rays detection at energies around 100 keV. Simulation, construction and detector performances of the FAMU apparatus at RAL are reported in this paper

First FAMU observation of muon transfer from \u3bcp atoms to higher-Z elements

Abstract: The FAMU experiment aims to accurately measure the hyperfine splitting of the ground state of the muonic hydrogen atom. A measurement of the transfer rate of muons from hydrogen to heavier gases is necessary for this purpose. In June 2014, within a preliminary experiment, a pressurized gas-target was exposed to the pulsed low-energy muon beam at the RIKEN RAL muon facility (Rutherford Appleton Laboratory, U.K.). The main goal of the test was the characterization of both the noise induced by the pulsed beam and the X-ray detectors. The apparatus, to some extent rudimental, has served admirably to this task. Technical results have been published that prove the validity of the choices made and pave the way for the next steps. This paper presents the results of physical relevance of measurements of the muon transfer rate to carbon dioxide, oxygen, and argon from non-thermalized excited \u3bcp atoms. The analysis methodology and the approach to the systematics errors are useful for the subsequent study of the transfer rate as function of the kinetic energy of the \u3bcp currently under way

The FAMU experiment at RIKEN-RAL to study the muon transfer rate from hydrogen to other gases

The aim of the FAMU (Fisica degli Atomi Muonici) experiment is to realize the first measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen _Ehf s 1S , by using the RIKEN-RAL intense pulsed muon beam and a high-energy mid-infrared tunable laser. This requires a detailed study of the muon transfer mechanism at different temperatures and hence at different epithermal states of the muonic system. The experimental setup involves a cryogenic pressurized gas target and a detection system based on silicon photomultipliers-fiber beam hodoscopes and high purity Germanium detectors and Cerium doped Lanthanium Bromide crystals, for X-rays detection at energies around 100 keV. Simulation, construction and detector performances of the FAMU apparatus at RAL are reported in this paper