Assessment of Posidonia oceanica (L.) Delile conservation status by standard and putative approaches: the case study of Santa Marinella meadow (Italy, W Mediterranean)

The conservation status of the Posidonia oceanica meadow at Santa Marinella (Rome) was evaluated through both standard (bed density, leaf biometry, "A" coefficient, Leaf Area Index, rhizome production) and biochemical/genetic approaches (total phenol content and Random Amplified Polymorphic DNA marker). The bio-chemical/genetic results are in agreement with those obtained by standard approaches. The bed under study was ranked as a disturbed one, due to its low density, and high heterogeneity in leaf biometry, LAI values, "A" coefficient and primary production. This low quality ranking is confirmed by both mean phenol content in plants, quite high and scattered, and by the low genetic variability in the meadow, with a very high similarity of specimen at a local scale. Hence, these two putative approaches clearly identify the endangered conservation status of the meadow. They link plant biodiversity and ecophysiology to ecosystem 'health'. Furthermore, they are repeatable and standardizable and could be usefully introduced in meadows monitoring to check environmental quality

Impact De L’anthropisation Sur Les Variations SpatioTemporelles Et Du Peuplement Zooplanctonique: Exemple Des Retenues D’eau De Bongouanou (Afrique De L’ouest, CoteD’ivoire)

Cette étude vise à déterminer l’impact de l’anthropisation sur les variations spatiotemporelles et du peuplement zooplanctonique des lacs Ehuikro et Socotè situés au Centre-Est de la Côte d'Ivoire dans la région du Moronou. Le zooplancton a été échantillonné mensuellement d’avril 2017 à Mars 2018 à l’aide d’un filet à plancton de 60 µm de vide de maille. Au total 37 taxons ont été observés (24 Rotifères, 6 Copépodes, 3 Cladocères et 4 autres organismes). Les Rotifères constituent le groupe dominant et constituent 46 % de l’abondance totale. En termes de densité, les Rotifères sont largement dominés par les Brachionidae (51 %). Globalement, la richesse taxonomique et l’abondance les plus fortes ont été enregistrées pendant les saisons de pluies (54 %) contre 46 % en saisons sèches. La station Ehui 2 a eu la plus grande richesse taxonomique (26 taxons en saisons sèches et 25 taxons en saisons des pluies) et la station Soco 1 a donné 17 taxons en saisons sèches et pluvieuses. Les variables qui influencent fortement la diversité taxonomique et l’abondance sont: la conductivité, la température, le potentiel d’hydrogène, la teneur en solide dissout, la teneur en phosphore, la teneur en nitrate et la profondeur. Objectives: This study aims to determine the impact of anthropization on Spatio-temporal variations and zooplankton population of lakes Ehuikro and Socotè located in the center-east of Côte d'Ivoire in the region of Moronou. Method and results: Zooplankton was sampled monthly from April 2017 to March 2018 using a 60 µm mesh void plankton net. A total of 37 taxa were observed (24 Rotifers, 6 Copepods, 3 Cladocerans and 4 other organisms). Rotifers are the dominant group with (46%) of the total abundance. In terms of density, Rotifers are largely dominated by Brachionidae (51%). Globally, the highest taxonomic richness and abundance were recorded during the rainy seasons at 54% against 46% in the dry seasons. Ehui 2 station had the greatest taxonomic richness (26 taxa in dry seasons and 25 taxa in rainy seasons) and Soco 1 station gave 17 taxa in dry and rainy seasons. The variables strongly influencing taxonomic diversity and abundance are: conductivity, temperature, hydrogen potential, rate of dissolved solids, rate of phosphorus, rate of nitrate and depth

Chapter Posidonia oceanica monitoring system on the coast of Aegean Sea of Turkey

Seagrass monitoring is a basic tool for measuring the condition of meadows in parallel to the environmental conditions. Posidonia oceanica meadows are very sensitive to anthropogenic effects. In the present study, two monitoring stations of Posidonia oceanica meadows were established on the Aegean coasts of Turkey in the years 2018 and 2019, at 26 m depth in Ildır Bay (İzmir, Turkey), and at 33 m depth in Kara Ada (İzmir, Turkey). The P. oceanica meadows upper and lower limits were defined by balisage systems. In the laboratory, lepidochronological, morphometric, and phenological parameters were also studied

Trace metal concentrations in Posidonia oceanica of North Corsica (northwestern Mediterranean Sea): use as a biological monitor?

BACKGROUND: Within semi-closed areas like the Mediterranean Sea, anthropic wastes tend to concentrate in the environment. Metals, in particular, are known to persist in the environment and can affect human health due to accumulation in the food chain. The seagrass Posidonia oceanica, widely found in Mediterranean coastal waters, has been chosen as a "sentinel" to quantify the distribution of such pollutants within the marine environment. Using a technique similar to dendrochronology in trees, it can act as an indicator of pollutant levels over a timeframe of several months to years. In the present study, we measured and compared the levels of eight trace metals (Cr, Ni, Cu, Zn, As, Se, Cd, and Pb) in sheaths dated by lepidochronology and in leaves of shoots sampled from P. oceanica meadows collected from six offshore sites in northern Corsica between 1988 and 2004; in the aim to determine 1) the spatial and 2) temporal variations of these metals in these areas and 3) to compared these two types of tissues. RESULTS: We found low trace metal concentrations with no increase over the last decade, confirming the potential use of Corsican seagrass beds as reference sites for the Mediterranean Sea. Temporal trends of trace metal concentrations in sheaths were not significant for Cr, Ni, Cu, As or Se, but Zn, Cd, and Pb levels decreased, probably due to the reduced anthropic use of these metals. Similar temporal trends between Cu levels in leaves (living tissue) and in sheaths (dead tissue) demonstrated that lepidochronology linked with Cu monitoring is effective for surveying the temporal variability of this metal. CONCLUSION: Leaves of P. oceanica can give an indication of the metal concentration in the environment over a short time period (months) with good accuracy. On the contrary, sheaths, which gave an indication of changes over long time periods (decades), seem to be less sensitive to variations in the metal concentration in the environment. Changes in human consumption of metals (e.g., the reduction of Pb in fuel) are clearly reflected in both organs. These results confirm that P. oceanica is a good bioindicator of metals and a good biomonitor species for assessing Cu in the environment

Chapter Monitoring of Posidonia oceanica meadows in the Sicilian coasts under the Water Framework Directive (WFD)

The present paper aims to assess for the first time the ecological status of the Sicilian water bodies using the PREI (Posidonia oceanica Rapid Easy Index) method according to the Water Framework Directive (WFD, 2000/60/EC) requirements. The PREI is based on five metrics: shoot density, shoot leaf surface area, E/L ratio, depth of lower limit, and type of this lower limit. Monitoring of the 29 P. oceanica meadows allowed to classify the 20 WBs of Sicilian coasts in the first two levels of status: 10 as “high” and 10 as “good” with the PREI values ranged between 0,551 and 1