Arsenic concentrations in seagrass around the Mediterranean coast and seasonal variations

Arsenic’s occurrence in the environment could be due to human activities as well as to natural sources. In this study, Posidonia oceanica and Cymodocea nodosa are collected in 84 sites around the Mediterranean basin. In addition, both seagrass are collected monthly, in two sites (Calvi in Corsica and Salammbô in Tunisia). Arsenic concentrations in C. nodosa present seasonal variations in relation with spring phytoplankton blooms. For both species arsenic concentration is higher in the vicinity of geological sources (mining), lagoon outlets and industrial activities. Moreover, Mediterranean islands (Balearic, Sardinia, Corsica, Malta, Crete and Cyprus) and the Southern basin coastline exhibit lower concentrations in Arsenic than the rest of the Mediterranean basin. The wide spread distribution of these two species would encourage their use in a global monitoring network devoted to Arsenic contamination.peer-reviewe

Observation de Saccorhiza polyschides (Lightfoot) Batters (Phaeophycées, Straménopiles) en Algérie (mer Méditerranée): une illustration des voies d’expansion de l’aire de distribution.

International audienceIn the Mediterranean Sea, the north-east Atlantic seaweed Saccorhiza polyschides (Lightfoot) Batters is uncommon. The only permanent populations are located in the Alboran Sea near the Strait of Gibraltar and the Strait of Messina (Italy). In contrast, since the early 19th century, several sightings, on ship’s hulls or in harbours, reflect the dispersal of propagules which failed to establish in the Mediterranean. Here we report a new sighting of Saccorhiza polyschides, near the port of Jijel, Algeria. This first new record in the Mediterranean for more than a century indicates that the dispersal of propagules continues today. In addition, because of its spectacular size and ease of its observation, it sheds light on the expansion routes of a species at the limit of their current range area.En Méditerranée, la macroalgue du nord-est de l’Atlantique Saccorhiza polyschides (Lightfoot) Batters n’est pas commune. Les seules populations permanentes sont celles de la mer d’Alboran, près du détroit de Gibraltar et du détroit de Messine (Italie). Depuis le début du xixe siècle, plusieurs observations, sur des coques de bateaux ou dans des ports, traduisent la dispersion de propagules en Méditerranée; l’espèce n’y a pas dépassé le stade d’adventice. L’observation de Saccorhiza polyschides près du port de Jijel (Algérie), la première nouvelle observation en Méditerranée depuis plus d’un siècle, montre que la dispersion de propagules en Méditerranée se poursuit de nos jours. De plus, grâce à sa taille et à la facilité de son observation, elle contribue à illustrer les voies d’expansion d’une espèce à la limite de son aire actuelle de distribution

Mediterranean seagrass meadows : resilience and contribution to climate change mitigation. A short summary.

International audiencenot availabl

Setting up the Medposidonia Programme in the Mediterranean Region

The MedPosidonia programme, an initiative of the Regional Activity Centre for Specially Protected Areas (UNEP/MAP) supported by the Total corporate Foundation, aims at collecting information on the geographic distribution and evolution of Posidonia meadows (Posidonia oceanica) in four Mediterranean countries with a view to using these information to elaborate and/or adjust their conservation and sustainable use of biodiversity programmes. Within the framework of this programme, activities were performed at two locations in Algeria (Kouali Cove and El Kala coasts), three in Tunisia (Sidi Ali El Mekki coasts, Sousse/Monastir Bay and Kerkennah Island), two in Libya (Tripoli area and AM Al-Ghazala coasts) and two in Turkey (Gokceada Island and Mersin area). Several actions were carried out: (i) enhancement of national capacities by the means of training sessions, (ii) carrying out of general cartography works using side scan sonar (lower limit) and remote sensing, through satellite images, (upper limit) techniques, (iii) setting up of monitoring systems along the lower limit following a standardized protocol, (iv) general assessment of seagrass meadow location and vitality, and (v) assessment of the ecological status of the water body using Posidonia oceanica as a bio-indicator. All the data collected were included in a Geographic Information System that will be regularly updated

Setting up the Medposidonia Programme in the Mediterranean Region

The MedPosidonia programme, an initiative of the Regional Activity Centre for Specially Protected Areas (UNEP/MAP) supported by the Total corporate Foundation, aims at collecting information on the geographic distribution and evolution of Posidonia meadows (Posidonia oceanica) in four Mediterranean countries with a view to using these information to elaborate and/or adjust their conservation and sustainable use of biodiversity programmes

Descriptors of <i>Posidonia oceanica</i> meadows: use and application

The conservation of the coastal marine environment requires the possession of information that enables the global quality of the environment to be evaluated reliably and relatively quickly. The use of biological indicators is often an appropriate method. Seagrasses in general, and Posidonia oceanica meadows in particular, are considered to be appropriate for biomonitoring because of their wide distribution, reasonable size, sedentary habit, easy collection and abundance and sensitivity to modifications of littoral zone. Reasoned management, on the scale of the whole Mediterranean basin, requires standardized methods of study, to be applied by both researchers and administrators, enabling comparable results to be obtained. This paper synthesises the existing methods applied to monitor P. oceanica meadows, identifies the most suitable techniques and suggests future research directions. From the results of a questionnaire, distributed to all the identified laboratories working on this topic, a list of the most commonly used descriptors was drawn up, together with the related research techniques (e.g. standardization, interest and limits, valuation of the results). It seems that the techniques used to study meadows are rather similar, but rarely identical, even though the various teams often refer to previously published works. This paper shows the interest of a practical guide that describes, in a standardized way, the most useful techniques enabling P. oceanica meadows to be used as an environmental descriptor. Indeed, it constitutes the first stage in the process