Search results for "marine"

First Evidence of Contourite Drifts in the North-Western Sicilian Active Continental Margin (Southern Tyrrhenian Sea)

2021

We present the results of an integrated geomorphological and seismo-stratigraphic study based on high resolution marine data acquired in the north-western Sicilian continental margin. We document for the first time five contourite drifts (marked as EM1a, EM2b, EM2, EM3a, and EM3b), located in the continental slope at depths between ca. 400 and 1500 m. EM1a,b have been interpreted as elongated mounded drifts. EM1a,b are ca. 3 km long, 1.3 km wide, and have a maximum thickness of 36 m in their center that thins northwards, while EM1b is smaller with a thickness up to 24 m. They are internally characterized by mounded seismic packages dominated by continuous and parallel reflectors. EM2 is loc…

Effets du bruit marin sur le changement des poissons sparidés juvéniles entre les espèces et les stades de développement

2023

International audience; Marine noise is an emerging pollutant inducing a variety of negative impacts on many animal taxa, including fish. Fish population persistence and dynamics rely on the supply of early life stages, which are often very sensitive to disturbance. Impacts of marine noise pollution (MNP) on juvenile fish have rarely been investigated in temperate regions. This is particularly true for the Mediterranean Sea, which is considered as an MNP hotspot due to intensive maritime traffic. In this study, we investigate the relationship between MNP related to boat traffic and (i) assemblage structure and (ii) the density of juvenile fishes (post-settlers at different stages) belonging…

The adaptations to tube-dwelling life of Propsilocerus akamusi (Diptera: Chironomidae) larvae and its eutrophication-tolerant mechanisms

2019

Propsilocerus akamusi (Diptera: Chironomidae) is a dominant macroinvertebrate species in many eutrophic lakes in subtropical and temperate zones. P. akamusi larvae can migrate deep into the sediment (>30 cm) during summer where is no oxygen. However, to our knowledge, the specific adaptive tactics of its tube-dwelling life (>30 cm) and underlying mechanisms why this species is favored by nutrient-rich lakes remain limited. With the understanding above-mentioned issues, we can provide important information for the development of sensitive biomonitoring. We examined monthly morphological dynamics and physiological adaptations of P. akamusi to anoxic conditions, and environmental relationships…

Submarine Slope Failures Along the Northern Sicilian Continental Margin (Southern Tyrrhenian Sea) and Possible Implications for Geo-Hazard

2013

Mass wasting and downslope movements are common processes that have contributed to shape the northern Sicilian continental margin (southern Tyrrhenian Sea) since the Late Quaternary. Nevertheless, processes controlling their evolution are still partially unknown and a variety of geologic factors can be responsible for their formation. In this work we present an overview of the main mass wasting features (submarine canyons, landslides, debris flows) observed and mapped in different sectors of the northern Sicilian margin. The margin is characterized by a narrow, steep continental shelf (1-2°) and a very irregular and steep (6-8°) upper slope. The main aims of this work are: (1) to outline th…

Submarine canyon of the north-western Sicilian offshore (Southern Tyrrhenian Sea): variability in morphologies, sedimentary processes and tectonic se…

2013

Ski jumping takeoff in a wind tunnel with skis.

2011

The effect of skis on the force–time characteristics of the simulated ski jumping takeoff was examined in a wind tunnel. Takeoff forces were recorded with a force plate installed under the tunnel floor. Signals from the front and rear parts of the force plate were collected separately to examine the anteroposterior balance of the jumpers during the takeoff. Two ski jumpers performed simulated takeoffs, first without skis in nonwind conditions and in various wind conditions. Thereafter, the same experiments were repeated with skis. The jumpers were able to perform very natural takeoff actions (similar to the actual takeoff) with skis in wind tunnel. According to the subjective feeling of the…

Marine Invertebrates as Bioindicators of Heavy Metal Pollution

2015

The marine environment presents a range of anthropogenic contaminants. According to the World Health Organization, more than 100,000 chemicals are released into the global environment every year as a consequence of their production, use and disposal. The fate of a chemical substance depends on physical-chemical properties, in combination with the characteristics of the environment where it is released. Among the substances that accumulate in the sea, for anthropogenic activities, metals/metalloids have a leading position. Some of these have a biological role but their bioaccumulation is injurious. Chemical pollutants can cause effects on organisms, biodiversity and human health. Various eff…

Analysis of the effects of co-exposure to antibiotics and cadmium on sea urchin embryos

2014

In order to understand the mechanisms of responses to changes in the physical and chemical environment, as well as the mechanisms of developmental pathways, we investigated by RT-qPCR assays and light microscopy observations the impact of antibiotics and cadmium in P. lividus sea urchin embryos. In particular we inspected development and biomarkers for free radical damage and apoptosis. During development embryos were exposed to an antibiotic mix (Ab mix, usually added to sea urchin cultures) or to sulfamethoxazole/trimethoprim mix (TMP/SMX, usually added to aquacultures) and/or levels of 10-5, 10-4, 10-3 M CdCl2. Even though treatment with TMP/SMX apparently did not affect development, it …

Changement climatique et suivi de la biodiversité marine côtière aux Iles Kerguelen

2018

Nearshore marine habitats of the French sub-Antarctic islands concentrate a rich and unique biodiversity that is currently facing climate change and its still not well-understood and multifaceted effects. Understanding the impact of these changes and predicting the potential response of ecosystems requires advanced knowledge of marine life and the achievement of uninterrupted and long-term observing programs. The Proteker program, no. 1044 of the French Polar Institute Paul-Émile Victor, has been developped in partnership with the National Nature Reserve of French Southern Territories in order to establish an observatory of coastal marine biodiversity in the Kerguelen Islands and evaluate t…

Gas geochemistry of shallow submarine vents in the Aegean sea (Greece)

2017

The Aegean area, which is geodynamically very active, is characterised by intense seismic activity, presence of active volcanic systems and anomalous geothermal gradients. Like other regions of intense geodynamic activity it is also characterized by extensive geogenic degassing. Gas manifestations are not only widespread on land but are also very frequent underwater. Many of these, as for example those of Milos and Santorini, are known since long time and have been previously studied although the targets were generally the hot waters or the sediments affected by the emissions (Smith and Cronan 1978, Dando et al. 1995, Price et al. 2013, Megalovassilis 2014).The present study aims at produci…