70 research outputs found
Fattori di controllo della disponibilità alimentare per il benthos eterotrofo in ambienti costieri di interfaccia
No full textGli ecosistemi di interfaccia, sono rappresentati da tutti quegli habitat al confine tra terre
emerse continentali e ambienti acquatici. Essi sono la fase dinamica di incontro tra ambienti
largamente differenti (mare, terra, atmosfera) definita come “interfaccia”, nella quale è possibile
riconoscere la transizione da un sistema all’altro per la presenza di marcati gradienti fisico-chimici,
biologici ed ecologici. Nella fattispecie, questi ecosistemi sono rappresentati dagli ambienti costieri
di basso fondale e da ambienti intertidali di substrato duro. Essi sono i principali fornitori di beni e
servizi ecosistemici per le popolazioni costiere. In questa tesi si è studiato il ruolo della variabilità
sistemica in ambienti intertidali di bassofondo su alcuni aspetti salienti del funzionamento
ecosistemico, della biodiversità e in ultimis sulla relazione tra biodiversità e funzionamento
ecosistemico. L’obiettivo è stato quello di studiare l’effetto della variabilità fisica e chimica come
fattore di controllo nei due habitat modello (laguna e pozze intertidali) lungo le coste della Sicilia
nord-occidentale, sulle caratteristiche del cibo disponibile - proveniente da produzione primaria e
secondaria. I risultati di questo studio mettono in evidenza il ruolo determinante della variabilità
spaziale e temporale, la quale controlla ampiamente le dinamiche chimico fisiche e trofiche in
questi ambienti estremi. Ad esempio nello Stagnone di Marsala l’energia meccanica di attrito
innescata dalla sinergia vento/marea gioca un ruolo importante sulla disponibilità di cibo, favorendo
gli scambi tra il comparto sedimentario e la colonna d’acqua. La presenza di vegetazione smorza
l’entità degli scambi che divengono massimi quando le fanerogame marine sono rade o assenti. I
risultati degli esperimenti su gli ambienti di pozza, hanno dimostrato l’importanza di questi habitat
sotto molti aspetti. Le pozze di scogliera del Mediterraneo, le cui dinamiche fisiche e chimiche sono
azionate dalle escursioni mareali funzionano come veri e propri bio-reattori. In particolare, è stato
dimostrato che, ogni sei ore, per effetto dell’isolamento in emersione, le pozze di scogliera
triplicano il contenuto di materiale organico, il quale viene disperso nell’adiacente intertidale, al
momento del collegamento con il mare nella successiva alta marea. Dato l’elevatissimo numero di
pozze presenti lungo le coste rocciose, l’export di materia organica labile prodotta quotidianamente
è quantitativamente rilevante. Questo sink di energia contribuisce indubbiamente a favorire il
mantenimento degli elevati livelli di biodiversità tipici di questi ambienti del Mediterraneo.
I risultati di questo studio forniscono nuove informazioni utili alla comprensione del funzionamento
degli ecosistemi di interfaccia marino-costieri, che sono stati fino ad ora, la fonte più importante di
approvvigionamento per le popolazioni rivierasche di tutto il pianeta
Impact of breakwater relocation on benthic biodiversity associated with seagrass meadows of northern Adriatic Sea
No full textBreakwaters are man-made constructions utilized for preventing coastal erosion primarily from wave action. At the same time, defence structures, modifying currents and circulation can afect water quality and benthic assemblages. Assessing and minimizing the impact of these structures is a priority in human-modifed coastal ecosystems, such as the central northern Adriatic where breakwaters extend for hundreds of kilometres. We investigated the efects of breakwater relocation on benthic features and meiofaunal diversity. To do this, we conducted a before–after comparison of (2011–2017) the relocation, which occurred in 2015. The analysis was conducted comparing a sheltered site, characterized by the presence of seagrass meadows and a wave-exposed site. Sediment features and meiofaunal variables were altered by the relocation, especially in the areas colonized by seagrass meadows. Results presented here pointed out to an enrichment in organic matter, the loss of two sensitive taxa (Cumacea and Ostracoda) and a shift in the assemblage structure with the increase of the relevance of Copepoda and Polychaeta. These results indicate that the careful management of breakwater is crucial for planning adequate conservation practices and protecting seagrass habitats and their biodiversity.This study has been conducted in the framework of the Project MERCES funded from the European Union's Horizon
2020 research and innovation programme under Grant agreement no. 689518.
This paper reflects only the authors' views and the funders cannot be held responsible for any use that may be made of the information contained there in. Copyright © 2018. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http:// creativecommons.org /licenses/by/4.0/)
Marine soundscape as an additional biodiversity monitoring tool: A case study from the Adriatic Sea (Mediterranean Sea)
No full textAcoustic monitoring can provide essential information on marine environments, including insights into ecosystem functioning and marine biodiversity monitoring. However, data on species acoustic behavior and
ecoacoustics studies in the Mediterranean Sea are still extremely scarce and this limits our ability to use soundscape features in monitoring studies. Here we present the results of a soundscape investigation conducted on shallow hard bottoms of the Adriatic Sea (Central Mediterranean basin). We report the presence of diverse circadian rhythms recorded in two different months, July and September. A power spectral density (PSD) was used to assess the overall spectral composition over time, and the Acoustic Complexity Index (ACI), was identified as a proxy for marine sounds of biological origin. The dominant component of the biological soundscape was composed of snapping shrimps and fishes. Spectral characteristics varied significantly both daily and between the two months. For frequencies>620 Hz (i.e., associated to snapping shrimp activity), both PSD and ACI were higher in July than in September. The same circadian rhythm was reported in both sampling periods, with the presence of snaps for 24 h a day, but with significantly lower intensity during daylight hours and pitches at the beginning and ending of the night. At lower frequencies (i.e.,620 Hz (i.e., associated to snapping shrimp activity), both PSD and ACI were higher in July than in September. The same circadian rhythm was reported in both sampling periods, with the presence of snaps for 24 h a day, but with significantly lower intensity during daylight hours and pitches at
the beginning and ending of the night. At lower frequencies (i.e.,<620 Hz), fish vocalizations mostly occurred during the night. Higher values of ACI were recorded during the night in both months, whereas the presence of anthropogenic noise caused opposite results in PSD levels. Noise was associated with higher PSD and ACI at the peak frequency of the snaps, suggesting a stimulation in snapping activity. Our findings provide new insights on the marine biological soundscape and on the potential use of ecoacoustics in future monitoring programs.This manuscript has been financially supported by the Project DEVOTES funded by the European Union under the 7th Framework Programme (Grant Agreement No. 308392), and by EU Horizon2020 project MERCES (Grant agreement n. 689518). We thank the KOMAROS scuba-diver association for providing support in completing the checklist of fish species of the study area. This paper reflects only the authors' views and the funders cannot be held responsible for any use that may be made of the information contained there in. Copyright © 2016. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http:// creativecommons.org /licenses/by/4.0/)
Biodiversity and distribution of meiofauna in the Gioia, Petrace and Dohrn Canyons (Tyrrhenian Sea)
No full textHabitat heterogeneity is a major structuring agent of benthic assemblages promoting high turnover in species composition and ultimately contributing to overall higher diversity. Submarine canyons, a pervasive feature of the continental margins worldwide, increase habitat heterogeneity at multiple spatial scales. In the present study, we test the hypothesis that different topographic structures or/and food sources controlling the abundance, biomass and biodiversity (using meiofauna and nematodes as a model study) in canyon systems. To do so, we compared different topographic structures: canyon edge, thalweg and axis, and the upper shelf and open slope in the Gulf of Gioia (Gioia and Petrace Canyons) and in the Gulf of Naples (Dohrn Canyon) (Tyrrhenian Sea) at different depths. Our results suggest that meiofaunal abundance and biomass are generally higher in the canyon thalwegs than in the canyon edge or adjacent open slopes at regional scale. This pattern is not always confirmed for biodiversity and when thalwegs are compared to different topographic structures within the Gioia Canyon system. In our study, the role of food quantity and quality is preeminent to explain the spatial distribution of meiofaunal variables among different topographic structures at 200-m while habitat heterogeneity become relevant at 500-m and within the Dohrn Canyon. In Gioia and Petrace Canyons we observed a high food availability is associated to specific topographic structures (thalwegs) that influenced the meiofaunal abundance and diversity distribution and nematode diversity and species composition. Each topographic structure shows a high number of exclusive species that contributes to a high species turnover and high overall biodiversity in all canyon systems. Changes in nematode composition determine also differences in the functional diversity (trophic guilds composition) and life strategy of the nematode assemblages. Our findings reveal that the presence of different topographic structures influences the spatial distribution of food quality and quantity that determine the presence of exclusive taxa and species enhancing both local and regional diversity
La materia organica disponibile per i bivalvi filtratori nei laghetti di tindari (Sicilia Nord-Orientale)
No full textMuscle Activity During Sleep in Human Subjects, Rats, and Mice: Towards Translational Models of Rem Sleep Without Atonia.
No full textStudy Objectives
rapid-eye-movement (REM) sleep without atonia (RSWA) is a marker of REM sleep behavior disorder (RBD) and is common in narcolepsy. Available techniques for electromyogram (EMG) analysis are species-specific, limiting translational research on RSWA. We developed an automated technique based on distributions of normalized EMG values (DNE) to overcome this limitation. With DNE, we tested whether the control of neck and tibialis anterior (TA) muscles during sleep in wild-type rats and mice validly models the control of submentalis (chin) and TA muscles in healthy humans. We then applied DNE to REM sleep recordings of patients with idiopathic RBD and of mouse models of narcolepsy, testing for a common DNE signature of RSWA.
Methods
retrospective analysis of sleep recordings from 20 idiopathic RBD patients, 34 control subjects, 8 wild-type rats, 21 orexin-neuron deficient mice, 8 orexin knock-out mice, and 22 wild-type mice.
Results
neck EMG of rats and mice and human chin EMG progressively decreased from wakefulness to non-REM sleep and REM sleep, whereas the effects of sleep on TA EMG differed between rats, mice, and humans. DNE discriminated idiopathic RBD patients from controls based on higher median values of normalized chin EMG during REM sleep. The same parameter, computed on neck muscle EMG, discriminated narcoleptic mice from wild-type mice.
Conclusions
these results support the application of DNE in translational research on RSWA. Increased median values of normalized EMG of chin (humans) and neck (rats and mice) muscles may be a signature of RSWA in different species and pathological conditions
High diversity of benthic bacterial and archaeal assemblages in deep-Mediterranean canyons and adjacent slopes
No full textImpact of hypersaline brines on benthic meio- and macrofaunal assemblages: A comparison from two desalination plants of the Mediterranean Sea
No full textGrowing water demands and decreasing water supplies are exacerbating water scarcity, which is one of the challenges for sustainable development. Desalination is expanding worldwide, particularly in the Mediterranean region and plants discharge at sea large amounts of hypersaline brines, which might have consequences on marine life. We report the results of the effects of brine discharge on sediments' biogeochemistry and benthic fauna (meiofaunal and macrofaunal abundance, diversity, taxonomic composition) of two desalination plants of the Mediterranean Sea, characterized by different desalination capacity and different environmental conditions. Brine discharge causes accumulation of organic matter and alteration of its biochemical composition in sediments downstream of the discharge point and along the direction of the main current, but only within few meters. The responses of faunal assemblages depend on the characteristics of the plants, the brine discharged and the consequent changes in the amount and quality of trophic resources. We conclude that direct and indirect impacts of desalination on benthic fauna, although of local interest, can reach a larger spatial scale depending on the amount of the brine produced and the hydrodynamic conditions. Therefore, future plants to be truly eco-sustainable should assess case-by-case the potential impacts of brine discharge on marine habitats
Effects of an Adélie penguin colony on coastal meiofaunal assemblages of the Ross Sea (Antarctica)
No full textFactors shaping biodiversity and functioning of coastal ecosystems in Antarctica are still largely unknown due to the overlap of multiple physical and bio-ecological forcings. Here, we investigated three coastal areas of the Ross Sea (Antarctica) across a coast-offshore transect (25–140 m depth), including an area located in front of the longest-dwelling penguin colony of the Adélie Cove Bay and other two areas, Camp Icarus Bay and Rod Bay, far from the penguin colony. The deposition of the penguin guano determined an extraordinary accumulation of organic matter in coastal sediments (6.9 ± 0.6 mgC g−1), among the highest values reported worldwide so far, which cause apparent detrimental effects on meiofaunal biodiversity, in terms of richness of taxa and nematode species. Meiofaunal abundance showed a wide spatial variability among bays and depths (range: 252 ± 103 to 5961 ± 659 ind. 10 cm−2) with lower abundance and biomass at shallow stations. Here, we found a limited food availability possibly associated with the occurrence of the ice-scouring along the coast. Overall, 17 meiofaunal higher taxa were identified and the richness of taxa reached the highest values at 140 m depth in all the three bays investigated. Nematodes were characterized by a high diversity with 100 species identified. A relevant number of exclusive
nematode species was observed in each bay and only 16 species were common at all sampling areas. The huge variability of biodiversity among the investigated areas was apparently related to a combination of biological (food availability and trophic interactions) and physical (ice-scouring) factors generating a mosaic of different assemblages. The combination of these factors determined a high turnover (beta) diversity (up to 100% of turnover for meiofaunal rare taxa and 81% for nematode species), which is likely a key driver for the high regional biodiversity observed in the coastal Antarctic sediments
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