Mediterranean Research Articles

From a validated targeted method to a retrospective UHPLC-HRMS non-targeted analysis unveiling COVID-19-related contaminants in clams. Have we bias in marine model organisms for ecotoxicological studies?

This study explores a retrospective non-targeted analysis (NTA), based on Ultra High-Performance Liquid Chromatography coupled to High-Resolution Mass Spectrometry (UHPLC-HRMS), to assess hidden chemicals of emerging concern (CECs) in marine model organisms. Conventional ecotoxicological studies do not include evaluating the natural habitats of the collected organisms, missing the possibility of highlighting unexpected pollutants, and thus compromising the correctness and reliability of the experimental results. In this paper we reprocessed samples previously collected from the Venice Lagoon for ecotoxicological studies and used for targeted analysis of three bisphenols-related compounds (i.e. BPS, BPF and BPAF) on seawater and specimens of the clam Ruditapes philippinarum. Results from the validation were the following: accuracy, expressed as percentage recoveries (R%), in the range 80%<R%<120% for all the considered compounds and matrices, and precision, expressed as relative standard deviation of the absolute areas of IS, was <20% for clams (N = 24) and <15% for seawater (N = 30). LODs ranged from 5 to 50 ng/L for seawater and 5–12 ng/g for clam tissues.After validation, a retrospective NTA was carried out on control samples, showing the presence of some CECs, i.e. Lopinavir, Ritonavir, DEHS, and DEHA, two antiviral drugs used during the COVID-19 pandemic and two plasticizers, respectively, reported here for the first time in the Mediterranean Sea. CEC identifications were confirmed by matching MS/MS spectra with libraries. The present study emphasizes the importance of retrospective investigations to describe the contamination scenario of environmental matrices and the related effect in biota, to correctly address studies on model animals, also including possible “cocktail effects”.

Impact assessment of multiple pressures on ecosystem services with a state and transition model: Application to Posidonia oceanica seagrass meadows

A significant challenge in the integration of ecosystem services into decision-making processes lies in effectively capturing the dynamics of marine socio-ecological systems, including their evolutionary pathways, equilibrium states, and tipping points. This paper explores the evolutionary trajectories of a vital marine ecosystem endemic to the Mediterranean Sea: the Posidonia oceanica seagrass meadows, in response to various drivers of change. A state-and-transition model is employed to assess the ecosystem services provided by P. oceanica across different states defined by selected transitions, such as overfishing, fragmentation, pollution, and invasion by non-native species. To apply this model, scientific expertise is combined with field data generated using the Ecosystem-Based Quality Index to evaluate the conservation status of P. oceanica. This integrated approach allows for the representation of the ecosystem services offered by the meadows across different states, leveraging ecological data. The findings highlight the disproportionate impact on provisioning services, particularly sea urchins and commercial fish production, which suffer the most under various stressors. Notably, when these services decline to critical levels, the meadows cease to provide significant benefits. Finally, a synthesized representation is presented, merging ecological insights with monitoring data, offering a framework that is more accessible to stakeholders and decision-makers.

A comprehensive analysis of spatial and temporal patterns of anthropogenic adult mortality of Bonelli's eagles in eastern Spain

AbstractIn eastern Spain, Bonelli's eagle (Aquila fasciata) abundance has declined almost 50% in the last 25 years and, consequently, the species is listed as regionally endangered. Therefore, the aim of this study is to report the mortality causes of territorial breeding Bonelli's eagles, including the spatial and temporal patterns, and to assess the effects on population dynamics. From 2015–2023, we tracked 60 Bonelli's eagles via global positioning system‐global system for mobile communications (GPS‐GSM) telemetry; 33 of the eagles died (median survival time = 1,519 days). Survival did not differ in relation to sex, age at capture (subadult vs. adult birds), breeding site (coastland vs. inland territories), or transmitter's model. One‐year probability of survival (95% CI) was 0.716 (0.607–0.845); 2‐year survival was 0.640 (0.524–0.781); and 3‐year survival was 0.581 (0.464–0.729). Anthropogenic mortality (66.7% of cases) prevailed over natural (27.3%) and unknown causes (6.0%). Causes of mortality were intra‐ and interspecific predation (24.2% of cases), electrocution (18.2%), poisoning (15.1%), collision with power lines (9.1%), shooting (9.1%), drowning (9.1%), collision with other man‐made infrastructure (6.1%), and disease (3.0%). Deaths were most frequent during the early breeding season. Only 2 (6.1%) of 33 deaths recorded occurred within a protected area. Natural causes of mortality were more frequent away from the Mediterranean coast. In contrast, anthropogenic deaths were more frequent near the Mediterranean coast, where human population density is high. We estimated that probability of extirpation of the species in our study area is 17.8% in the next 50 years and 99.2% in 100 years. Nonetheless, a small reduction in adult mortality by ≥15% could prevent extirpation in the next 50 years. Therefore, actions to reduce adult mortality are urgently needed to preserve the Bonelli's eagle in eastern Spain.

Microalgae in the Mediterranean area: A geographical survey outlining the diversity and technological potential

Microalgal diversity enables the possibility to employ them in technological applications, as widely shown by the modern literature. While there exists an extensive body of literature concerning the technological applications of microalgae, the scientific knowledge of microalgal species remains relatively limited. Therefore, there is still potential for unlocking new opportunities through the study of the microalgal biodiversity, particularly in the Mediterranean region, which is unique because of its sub regional diversity. While some studies have assessed microalgae distribution in the Mediterranean area, and others have focused on specific aspects of their technical exploitation, this review seeks to offer a comprehensive overview of isolated microalgal species and their technological applications. Microalgae from the Mediterranean area share common characteristics, such as low half-saturation constants and acclimation to high light intensity, making them ideal for specific technological applications. While the search for new microalgae for technological purposes can help in biodiversity conservation, numerous species still remain underexplored, offering potential for innovative applications. However, the key finding from the critical analysis of the literature is that the diversity of microalgae in the Mediterranean region is its true richness, allowing for their versatile applications across various processes. The work focuses on the Mediterranean area, i.e., having coastlines along the Mediterranean Sea and on aquatic microalgae, coming from water with different salinity levels. This review offers an intrinsic ecological and technological perspective and provides a fresh outlook on the microalgal sector, promoting its expansion in the Mediterranean area and the development of sustainable bio-industries.

Constraints on the energy spectrum of the diffuse cosmic neutrino flux from the ANTARES neutrino telescope

High-significance evidences of the existence of a high-energy diffuse flux of cosmic neutrinos have emerged in the last decade from several observations by the IceCube Collaboration. The ANTARES neutrino telescope took data for 15 years in the Mediterranean Sea, from 2007 to 2022, and collected a high-purity all-flavour neutrino sample. The search for a diffuse cosmic neutrino signal using this dataset is presented in this article. This final analysis did not provide a statistically significant observation of the cosmic diffuse flux. However, this is converted into limits on the properties of the cosmic neutrino spectrum. In particular, given the sensitivity of the ANTARES neutrino telescope between 1 and 50 TeV, constraints on single-power-law hypotheses are derived for the cosmic diffuse flux below 20 TeV, especially for power-law fits of the IceCube data with spectral index softer than 2.8.

Numerical simulations of the region of possible sprite inception in the mesosphere above winter thunderstorms under wind shear

Transient luminous events (TLEs) is the collective name given to mesospheric electrical breakdown phenomena occurring in conjunction with strong lightning discharges in tropospheric thunderstorms. They include elves, sprites, halos, and jets, and are characterized by short lived optical emissions, mostly of red (665 nm) and blue (337 nm) wavelengths. Sprites are caused by the brief quasi-electrostatic field induced in the mesosphere, mostly after the removal of the upper positive charge of the thundercloud by a +CG, and they have been recorded above most of the lightning activity centers on Earth. In wintertime, there are just a few areas where lightning occurs, and of those, sprites have been observed over the Sea of Japan, the British Channel, and the Mediterranean Sea. Unlike their summer counterparts, winter thunderstorms tend to have weaker updrafts and as a result, reduced vertical dimensions and compact charge structures, whose positive and negative centers are located at lower altitudes. These storms are often susceptible to significant wind shear and as a result may exhibit a tilted dipole charge structure and a lateral offset of the upper positive charge relative to the main negative charge. We present results of numerical simulations using a three-dimensional explicit formulation of the mesospheric quasi-electrostatic electrical field following a lightning discharge from a typical mid-latitude winter thunderstorm exhibiting tilt due to wind shear and evaluate the regions of possible sprite inception. Our results show, as numerous observations suggest, that sprites can be shifted a large distance from the location of the parent +CG in the direction of the shear and will occur over a larger region compared with non-sheared storms.

Ecological genomics in the Northern krill uncovers loci for local adaptation across ocean basins

Krill are vital as food for many marine animals but also impacted by global warming. To learn how they and other zooplankton may adapt to a warmer world we studied local adaptation in the widespread Northern krill (Meganyctiphanes norvegica). We assemble and characterize its large genome and compare genome-scale variation among 74 specimens from the colder Atlantic Ocean and warmer Mediterranean Sea. The 19 Gb genome likely evolved through proliferation of retrotransposons, now targeted for inactivation by extensive DNA methylation, and contains many duplicated genes associated with molting and vision. Analysis of 760 million SNPs indicates extensive homogenizing gene-flow among populations. Nevertheless, we detect signatures of adaptive divergence across hundreds of genes, implicated in photoreception, circadian regulation, reproduction and thermal tolerance, indicating polygenic adaptation to light and temperature. The top gene candidate for ecological adaptation was nrf-6, a lipid transporter with a Mediterranean variant that may contribute to early spring reproduction. Such variation could become increasingly important for fitness in Atlantic stocks. Our study underscores the widespread but uneven distribution of adaptive variation, necessitating characterization of genetic variation among natural zooplankton populations to understand their adaptive potential, predict risks and support ocean conservation in the face of climate change.

Subdividing a Cretaceous Carbonate Reservoir in the East Mediterranean Sea, Egypt, Based on Petrographical Characteristics: A Case Study

Subdividing a Cretaceous Carbonate Reservoir in the East Mediterranean Sea, Egypt, Based on Petrographical Characteristics: A Case Study

Expression and Transcriptional Targets of TGFβ-RII in Paracentrotus lividus Larval Skeletogenesis.

Organisms from the five kingdoms of life use minerals to harden their tissues and make teeth, shells and skeletons, in the process of biomineralization. The sea urchin larval skeleton is an excellent system to study the biological regulation of biomineralization and its evolution. The gene regulatory network (GRN) that controls sea urchin skeletogenesis is known in great details and shows similarity to the GRN that controls vertebrates' vascularization while it is quite distinct from the GRN that drives vertebrates' bone formation. Yet, transforming growth factor beta (TGF-β) signaling regulates both sea urchin and vertebrates' skeletogenesis. Here, we study the upstream regulation and identify transcriptional targets of TGF-β in the Mediterranean Sea urchin species, Paracentrotus lividus. TGF-βRII is transiently active in the skeletogenic cells downstream of vascular endothelial growth factor (VEGF) signaling, in P. lividus. Continuous perturbation of TGF-βRII activity significantly impairs skeletal elongation and the expression of key skeletogenic genes. Perturbation of TGF-βRII after skeletal initiation leads to a delay in skeletal elongation and minor changes in gene expression. TGF-β targets are distinct from its transcriptional targets during vertebrates' bone formation, suggesting that the role of TGF-β in biomineralization in these two phyla results from convergent evolution.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) distribution, origins, and risk evaluation in the Egyptian Mediterranean coast sediments.

A study was conducted on 31 surface sediments located in different sectors of the Egyptian Mediterranean coast. The sediments were analyzed for their pollution levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The sediments were collected from various depths in harbors, coastal lakes, bays, and lagoons, covering the southeastern Mediterranean of the Nile Delta region. The study aimed at determining the distribution, origin, and potential ecological impact of OCP and PCB pollutants. The researchers used the SRM method of GC-MS/MS to measure the concentration of 18 PCBs and 16 OCPs residues. The study found that the total concentration of OCPs in the samples ranged from 3.091 to 20.512 ng/g, with a mean of 8.749 ±3.677 ng/g. The total concentration of PCB residues ranged from 2.926 to 20.77 ng/g, with a mean of 5.68 ±3.282 ng/g. The concentration of DDTs exceeded the effect range low (ERL) (1.00) and threshold effect level (TEL) (1.19) in several stations, but it was still below the effect range median (ERM) (7.00) and the probable effect level (PEL) (4.77). This indicates a low ecological risk. The principal component analysis (PCA) was also conducted to determine the sources of all pollutants in the sediment. The PCA showed significant correlations between the concentrations of Gama-HCH and Beta-HCH (0.741), suggesting similar sources. PRACTITIONER POINTS: OCPs and PCBs residues were analyzed in the sediment of the southeastern Mediterranean. The concentration, existence, and causes of OCPs and PCBs were investigated. OCPs and PCBs ecological risk and ecotoxicological calculation were investigated in detail. Cluster analysis, PCA, and correlation coefficient were also investigated.

Blue shark vertical movement patterns in the Central Mediterranean: bycatch mitigation windows revealed from pop-up satellite archival tag data

In the Mediterranean Sea, pelagic longline fisheries, targeting tuna and swordfish, have contributed significantly to the bycatch of threatened chondrichthyan species, such as blue shark (Prionace glauca). The Mediterranean blue shark population is assessed as critically endangered, making a timely implementation of mitigation measures crucial. A comprehensive understanding of blue shark habitat use dynamics is essential for deriving appropriate mitigation measures. This study aimed at evaluating vertical movement behaviour and investigating factors potentially influencing the movements of blue sharks in the Mediterranean Sea. Twenty-six blue sharks, bycaught in a longline fishery in the southern Adriatic, were tagged with pop-up satellite archival tags. Analysis of data from thirteen recovered tags revealed a distinctive diel movement pattern. Blue sharks used shallower waters during the night and deeper waters during the day, characterised by steep ascents and descents during sunset and sunrise, respectively. In addition, lunar phases were also influencing the depth of blue shark movements, with sharks using deeper waters right before and during full-moon. Shark size, salinity, currents, spatial location and time of the year were additional factors influencing blue shark depth use. The observed tendency of blue sharks to use deeper areas at daytime and prior and during the full moon period offers possibilities to develop and test bycatch mitigation strategies. Aligning longline fishing schedules and fishing depths with blue shark behaviour during the fishing seasons could hold promise to effectively reduce spatio-temporal overlap between fishing and blue shark distribution and may ultimately decrease the bycatch impact of the fishery.

Rising Temperatures, Wavering Human Towers? Temperature Trends and Thermal Comfort during Castells Exhibitions in Catalonia (1951–2023). Case Studies in Valls (24 June), La Bisbal del Penedès (15 August), Tarragona (19 August), and Vilafranca del Penedès (30 August)

This study analyzes temperature trends and thermal comfort during the key hours (i.e., from noon to 3:00 p.m.) of human tower (castells) performances in four significant festivities involving this outdoor exhibition (diada castellera) in Catalonia. Human towers were recognized by UNESCO in 2010 as an Intangible Cultural Heritage. The selected exhibitions were Sant Joan in Valls on 24 June; Festa Major de La Bisbal del Penedès on 15 August; Sant Magí in Tarragona on 19 August; and Sant Fèlix in Vilafranca del Penedès on 30 August. Temperature and relative humidity data were downloaded from the Copernicus Climate Change Service’s ERA5-Land and ERA5 pressure level datasets, respectively, with reanalysis from 1951 to 2023. The results revealed a clear upward trend in temperatures over the last several decades in these four places and for the respective dates, from +0.3 °C per decade in La Bisbal del Penedès to +0.42 °C per decade in Valls. Most of the positive temperature anomalies were concentrated in the last 25 years. The calculation of the Heat Index revealed a higher occurrence of years with possible fatigue due to prolonged exposure and/or physical activity in the three inland locations (i.e., Valls, La Bisbal del Penedès, and Vilafranca del Penedès) and a greater frequency of years with possible heat stroke, heat cramps, and/or heat exhaustion in Tarragona, which is near the Mediterranean Sea. This warming trend and increased discomfort pose potential health risks for participants and suggests a need for adaptive measures. These findings emphasize the importance of incorporating climate considerations into human tower planning.

Spatial distribution of soil rare earth elements in Sicily (Italy)

Rare earth elements (REEs) are becoming increasingly interesting as indicators of soil processes, and modelling their spatial distribution has become a fundamental requirement for this purpose. This study aims to model and quantify the spatial distribution of soil REEs taking into account their compositional nature in their mapping, and to assess the associated spatial uncertainty. In particular, the cerium anomaly (Ce⁎) and the ratio of the sum (Σ) of light to heavy REEs (ΣLREEs/ΣHREEs) were calculated and analysed. The study was carried out in Sicily (Italy), one of the largest (25,832 km2) and most populous island in the Mediterranean Sea. Soil REE data were obtained from the soil database of Sicily region. Soil REEs were transformed into a vector of isometric log-ratio (ilr) coordinates and analysed using a geostatistical approach for predicting their values at unsampled locations and generating 100 REEs realizations using turning bands simulation. Each REE element and Ce⁎ were mapped as well as the ΣLREEs/ΣHREEs ratio. The joint variability of the investigated REEs and the ΣLREEs/ΣHREEs ratio provided insights into their abundance and distribution patterns. From the simulated realizations, standard deviation maps were calculated for the Ce⁎ and the ΣLREEs/ΣHREEs ratio, providing a measure of their spatial uncertainty. Although with some limitations, the study established a first baseline of the Ce⁎ and the ΣLREEs/ΣHREEs ratio. The maps of spatial uncertainty may be a useful tool for planning future soil sampling and optimise the choice of new sampling locations.

Demographic regulation processes in Pinna nobilis population subunits: Implications for restocking

A mass mortality event (MME) affected the endemic bivalve Pinna nobilis across the Mediterranean Sea in autumn 2016. This event affected specimens of all sizes, depth ranges and habitat types, resulting in a drastic decline in the species population close to 100%. Indeed, the consequences of a potential recovery, and therefore the viability of the populations of the species are unknown. To evaluate the likelihood of success when designing the reintroduction of the species in optimal areas, knowledge of population dynamics is essential. Here we compare two population subunits of Pinna nobilis from two areas with different environmental conditions, located in Cabrera National Park (protected area with low exposure to hydrodynamic activity) and San Telmo (unprotected area exposed to hydrodynamic activity), both in the Balearic Islands. A total of 259 individuals were tagged and monitored annually between 2011 and 2014, prior to the MME. Matrix population models were used to reduce the complexity of the age-structured population dynamics and assessing the degree of elasticity of the population. We showed that the subunit of San Telmo showed highly variable values of demographic rates, higher stochasticity and higher sensitivity to environmental variability than the population subunit of Cabrera National Park. The study shows the importance of the buffering effect of a large population as there are many adult individuals of many size classes in the population subunit of Cabrera National Park, as its age structure helps to cope with highly variable reproductive success. Therefore, these population subunits are more stable regardless of depth and would be a more suitable site for future reintroduction programs.

Apis florea in Europe: first report of the dwarf honey bee in Malta

ABSTRACTS The Red dwarf honey bee (Apis florea), is a single-comb open-nesting member of the genus Apis with a natural distribution area stretching from the Indomalayan realm on the east to the Persian Gulf on the west. However, it is reportedly colonising new territories mainly due to anthropogenic activities. Nowadays it can be found from Taiwan on the east, to Jordan, the Arabian Peninsula and North-eastern Africa on the west. Here we present the first scientific record of a fully established colony of A. florea in Europe. The colony was found on Malta, a crossway of naval routes in the Mediterranean Sea. We documented the incident with photos, collected samples of workers and drones and sequenced the mtDNA COI gene to confirm assignment to A. florea. Also, we alert the competent authorities and the beekeeping community to be vigilant and ready to undertake effective eradication measures. In the paper, we discuss the risks and the potential consequences associated with the invasion of A. florea in Europe.

Sources of PM10 ionic species in the South-West Mediterranean (Algeria).

The contents of water-soluble major's ions (MSA, Cl-, NO3-, SO42-, Na+, NH4+, K+, Mg2+, and Ca2+) in the PM10 particle fraction were investigated thanks to detailed measurements of the main chemical constituents of PM10 in remote coastal areas in Bou-Ismail; in the South-West of the Mediterranean Sea (Algeria), during a 2-year period; from July 2011 to August 2013, under the framework of the ChArMEx project (Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr ). The total water-soluble ion concentrations in PM10 at the Bou-Ismail measurement station varied from 3.3µg/m3 (July 2011) to 49.6µg/m3 (March 2012). The annual mean mass concentrations of ions in the PM10 particulate fraction were Cl- > Na+ > SO42- > Mg2+ > NO3- > Ca2+ > K+ > NH4+ > Oxalate. The change in potassium nss-K + concentrations in PM10 over the course of a year reveals that biomass burning (BB) has an effect on three separate seasons: the beginning of winter (February and March), the end of summer (August), and the autumn (September and October). The origin periods of biomass burning BB identified employing the mapping of hotspots and fires during periods of August and September 2011, 2012, and 2013 underlined the important fires in the surrounding areas of the Mediterranean Sea (Sardinia Islands from Italy, Corsica from France).

Field study on natural phytoplankton throughout “Bizerte City” oil spill on the south-western coast of the Mediterranean Sea

Field study on natural phytoplankton throughout “Bizerte City” oil spill on the south-western coast of the Mediterranean Sea

Planktonic foraminifera response to the azores high and industrial-era global warming in the central-western Mediterranean Sea

The Mediterranean Sea is warming about 20 % more rapidly than global ocean and this phenomenon is impacting ecosystems and biodiversity. Planktonic foraminifera are an important component of surface and subsurface water ecosystems and food chains. Their species communities have been altering across the oceans since the Industrial Era, in response to the ongoing climate change, especially in the western Mediterranean Sea, where a significant productivity decrease has been recently reported.Here we show planktonic foraminifera and multispecies stable isotopes from three short sediment cores, recovered on the eastern flank of the Sicily Channel, central Mediterranean Sea. Results fully confirm the planktonic foraminifera productivity decrease in the Industrial Era, which is especially relevant for the second half of the 20th century. The planktonic foraminifera productivity decrease matches with a higher number of Large Azores High events, i.e., the establishment of an exceptional and persistent winter atmospheric high-pressure ridge over the western-central Mediterranean Sea. This is an unprecedented atmospheric phenomenon for the last millennia Mediterranean Sea history, as a direct response of the global warming. Surface productivity and DCM species are especially declining since ∼1960 CE, at expenses of winter mixed layer taxa, suggesting that the Azores High activity prevents a sustained water column vertical mixing and surface water nutrient fuelling. Our results document and confirm that the climate change has already been affecting Mediterranean marine ecosystems and the basic level of the trophic chain, by extending the surface water stratification period.

Microplastic characterization in the stomachs of swordfish (Xiphias gladius) from the western Mediterranean Sea

In this study, we aimed to quantify the presence of microplastics (MPs) in the stomachs of large pelagic fish (swordfish, Xiphias gladius, Linnaeus, 1758) sampled in the western Mediterranean Sea, and assess temporal trends (2011–2012 vs. 2017–2019) in MP ingestion. MPs were extracted from stomachs and characterized by μ-Fourier transform infrared spectroscopy. Results highlighted the ingestion of MP in 39 out of 49 stomachs analysed. Ingested MPs consisted mostly of small (<1 mm) fibers (88.6 %, mean ± standard deviation = 2.5 ± 6.1 particles per stomach), with a greater frequency of occurrence (FO) in the second period (FO = 90 %, 3.3 ± 8.0 particles per stomach). The predominant colours were purple, black and blue, and polyethylene terephthalate was the most frequently detected polymer. These results are crucial for the development of management actions aimed at the conservation of swordfish in the Mediterranean Sea and the prevention of health risks to humans.

Isolation and identification of marine microalgae from Egyptian coasts as potential source of biodiesel: morphology and sequence-based screening

ABSTRACT Microalgae are a highly effective and renewable source of biodiesel that can be used as a substitute for petro-diesel in the global fuel market. In the present study, 14 water samples were collected from a variety of locations along the coastal areas of the Red Sea and the Mediterranean Sea in Egypt. These water samples, which contained microalgae, were subjected to enrichment process and standard procedures to obtain pure cultures. Based on morphological features, 27 microalgae isolates representing 12 different species were identified, with Chlorella species being the most dominant. Based on 18s rRNA gene sequencing, nine new native microalgae strains were identified, comprising four strains belonging to Chlorella species, two strains to Chlamydomonas, and one strain each of Phormidium, Nostoc, and Microcytosis species that could be appropriate for producing biodiesel. This information could be used to improve the knowledge on the composition of planktonic microalgal communities of Egypt and the target native species for biodiesel production.