The exergy of a phase shift: Ecosystem functioning loss in seagrass meadows of the Mediterranean Sea

Posidonia oceanica (L.) Delile meadows are considered as the most productive ecosystems of the Mediterranean basin, sequestering and storing significant amount of blue carbon in their rich organic sediments and in their living and non-living biomass and these meadows are identified as a priority habitat type for conservation under the Habitat Directive (Dir 92/43/CEE). Despite the importance of the ecosystem services it provides, this habitat is disappearing at a rate four times as high as that of terrestrial forests, experiencing an alarming reduction due to the impacts of human activities in coastal areas, especially in the north-western side of the Mediterranean Sea. To face this issue, the SeaForest Life project foresees the quantification of carbon deposits and their rate of change related to habitat degradation specifically focusing on the effects caused by boat&#8217;s anchors and moorings. The project is realized in the Archipelago of la Maddalena National Park, the Asinara National Park and the Cilento, Vallo di Diano and Alburni National Park, for which ad hoc management plans of mooring are going to be adopted to reduce the impact of this practice on the seagrass meadows. As a first step, an updating of habitat 1120*&#8217;s cartography in each of the Marine Protected Areas engaged in the project have been fulfilled, using high definition multispectral imagery. Furthermore, monitoring of the areas with the highest attendance of the anchorages was carried out through the use of medium resolution satellite multi-spectral images using the infrared band, to identify and quantify the degradation and the state of conservation of the P.oceanica meadows present in the investigated areas. The updated cartography has been used to implement the InVEST Coastal Blue Carbon (CBC) which attempts to predict the sequestration, storage and, when degraded, the emissions of carbon by coastal ecosystems, so representing a useful tool for the analysis of the ecological and economic effects of the degradation processes (boats anchoring) and mitigation measures (anchor management plan and eco friendly moorings). Up to now, the InVEST-CBC model has estimated a CO2 loss due to boats anchoring equal to 2300 tCO2/year, using stock and flow data in soil and biomass obtained from the results of the Life Blue Natura project and P. oceanica samples collected in the Cilento National Park. In the future, the results of the model will be improved with data collected in the other two project areas, also through the use of innovative instrumentation. Moreover, the scenarios with the implementation of the mooring management plans will be analyzed in the three study areas. The dataset obtained by the model is being used to define a standard protocol for the estimation of CO2 fixation by P. oceanica meadows in the Mediterranean Sea. Such protocol will be fundamental for the realization of a national IT-based platform for a voluntary based carbon market to sell and acquire the carbon credits generated by the SeaForest Life project activities, to be extended to all the Mediterranean countries and to be scaled up to new protected marine areas.

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High Diversity and Abundance of Foraminifera Associated with Mediterranean Benthic Red Algae Mats

Diversity ◽

10.3390/d14010021 ◽

2021 ◽

Vol 14 (1) ◽

pp. 21

Author(s):

Felix Ivo Rossbach ◽

Benedikt Merk ◽

Christian Wild

Keyword(s):

Mediterranean Sea ◽

Surface Area ◽

Red Algae ◽

Benthic Fauna ◽

Posidonia Oceanica ◽

Tyrrhenian Sea ◽

Pilot Studies ◽

Seagrass Meadows ◽

The Mediterranean ◽

High Diversity

The Mediterranean Sea comprises habitats such as Posidonia oceanica seagrass meadows that exhibit high associated biodiversity of sessile organisms. Recent pilot research indicates that benthic mats formed by the scarcely investigated fleshy red alga Phyllophora crispa also host a high diversity of benthic fauna. Among the key taxa found in these mats in the recent pilot studies are benthic foraminifera that live as epiphytes on the red algae thalli. Knowledge about their abundance and species richness associated with this habitat in relation to reference habitats is missing. We thus carried out a comparative assessment focusing on foraminifera within samples from P. crispa mats and neighboring P. oceanica meadows on five different sampling sites around Giglio Island in the Tuscan Archipelago (Tyrrhenian Sea, Italy). A total of 104 different foraminiferal taxa were identified, of which a total of 85 taxa were found in P. crispa samples (46 exclusively in this habitat). This biodiversity was higher compared to other studies on phytal habitats in the Mediterranean Sea. The number of foraminiferal taxa associated with P. crispa was significantly higher (average 27.5 ± 8.1 taxa) compared to P. oceanica (leaves average 7.0 ± 3.6, shoots average 7.9 ± 3.4 taxa). The abundance of foraminifera (12,000 individuals m−2 surface area of P. crispa mat) was also higher than in the neighboring P. oceanica meadows (7792 individuals m−2 leaf and 8171 individuals m−2 shoot surface area). The most frequently found taxa across habitats were Miniacina miniacea, Lobatula lobatula, and Sejunctella sp. (24%, 20%, and 6% of the total population, respectively). Our results imply that P. crispa mats host an exceptional diversity of associated foraminifera that is even higher than those associated with seagrass meadows. Red algae mats built by P. crispa may thus be considered as potential refuge habitats and biodiversity reservoirs in management and conservation.

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Amphipods from tidal channels of the Gulf of Gabès (central Mediterranean Sea)

Mediterranean Marine Science ◽

10.12681/mms.15913 ◽

2018 ◽

Cited By ~ 3

Author(s):

ABIR FERSI ◽

JEAN CLAUDE DAUVIN ◽

JEAN PHILIPPE PEZY ◽

LASSAD NEIFAR

Keyword(s):

Species Richness ◽

Mediterranean Sea ◽

Native Species ◽

High Energy ◽

Tidal Channels ◽

Central Mediterranean ◽

Gulf Of Gabes ◽

Seagrass Meadows ◽

Gulf Of Gabès ◽

The Mediterranean

The spatial and temporal species richness, abundance and assemblage structure of amphipods from four tidal channel of the Gulf of Gabès were studied at 26 stations and during four seasons from March 2016 to January 2017. This led to the identification of 4,278 individuals, 45 species and 21 families. The four mostly diversified families are the Ampeliscidae (6 species), the Caprellidae (5) and the Aoridae and Maeridae (4 species both), while three families account for ~ 75% of the individuals: Aoridae (45.5 %), Corophiidae (20.5%) and Dexaminidae (7.2%). The species richness and abundance were higher in winter than at other seasons. The fauna is dominated by a small number of species characteristic of areas with detritus accumulation and seagrass meadows, including Microdeutopus anomalus, Monocorophium acherusicum, Dexamine spinosa, Microdeutopus gryllotalpa, Cymadusa filosa and Elasmopus rapax, which are commonly recorded in lagoons and coastal shallow waters of the Mediterranean Sea. The amphipod structure is linked to the location of tidal channels in the Gulf of Gabès. Abundances are low in the Kerkennah channel compared with other channels, especially the Maltine channel with high winter accumulation of organic matter. There are also low abundances in high-energy hydrodynamic zones with gravel sediment; conversely, the presence of macrophytes, mainly in the seagrass meadows, increases amphipod diversity. As a result of this study, five new species can be added to the inventory of the Tunisian marine amphipod fauna, including a non-native species for the Mediterranean Sea, Paracaprella pusilla.

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On the Transfer Function between Surface Fields and the Geostrophic Stream Function in the Mediterranean Sea

Journal of Physical Oceanography ◽

10.1175/jpo-d-13-0186.1 ◽

2014 ◽

Vol 44 (5) ◽

pp. 1406-1423 ◽

Cited By ~ 16

Author(s):

Jordi Isern-Fontanet ◽

Mahesh Shinde ◽

Cristina González-Haro

Keyword(s):

Phase Shift ◽

Transfer Function ◽

Mediterranean Sea ◽

Mixed Layer ◽

Environmental Conditions ◽

Phase Shifts ◽

Sea Surface ◽

Qualitative Behavior ◽

The Mediterranean ◽

Mixed Layers

Abstract The real transfer function and the phase shift between sea surface height (SSH) and sea surface buoyancy (SSB) were estimated from the output of a realistic eddy-resolving model of the Mediterranean Sea circulation. The analysis of their temporal evolution unveiled the existence of a clear seasonal cycle closely related to that of the mixed layer depth. The phase shifts between SSH and SSB attain their minimum for deep mixed layers, which is different from zero. Besides, the spectral slope of the transfer function at scales shorter than 100 km fluctuates between k−1 and k−2. For deep mixed layers, it is close to k−1, as predicted by the surface quasigeostrophic (SQG) solution. At longer wavelengths, it is approximately constant under the different environmental conditions in all of the subbasins analyzed with the exception of the Gulf of Lions. The capability to observe sea surface temperature (SST) from satellites motivated the extension of this analysis to SST and SSH. Results showed a similar qualitative behavior but with larger phase shifts. In spite of the presence of a phase shift, even for deep mixed layers, results revealed that it is still possible to reconstruct surface dynamics from SST using a transfer function, provided that the mixed layer is deep enough. For the present study, a threshold value of 70 m was enough to identify the appropriate environmental conditions. In addition, the results revealed that a precise estimation of the transfer function significantly improves the reconstruction of the flow in comparison with the application of the classical SQG solution.

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