Growth performance of Cakile maritima Scop and Brassica tournefortii Gouan in relation to the regulation of some sodium-inducible genes at salt affected lands in the Nile Delta coast

Habitats differentiation between Cakile maritima Scop and Brassica tournefortii Gouan in the Nile Delta Coast, Egypt

ثلاجات ألبية | ثلاجات نرويجية | ثلاجات إيطالية | ارتفاع مستوى سطح البحر | تغيرات مناخية | الدفء العالمي | ساحل دلتا النيل | السد العالي | Alpine Glaciers | Norwegian Glaciers | Italian Glaciers | Sea Level Rise | Climate Changes | Global Warming | Nile Delta Coast | Aswan High Dam

The main objectives of the current work are (1) to determine historic pattern of shoreline changes (erosion and accretion) along the north coast of the Nile Delta, (2) to present a future view on what to be expected regarding climate change impacts, sea-level rise (SLR) scenarios, expected land losses and alteration of some soil characteristics (3) to recognize negative impacts of SLR on the Nile Delta coast and (4) to assess and suggest protection measures. The current investigation was conducted using the advanced techniques of remote sensing and geographic information system. The investigated area with 394 measured locations is located along the northern coast of the Nile Delta between Alexandria and ElTina plain in Sinai peninsula exactly between 29°20′ and 32°40′ E and 29°54′ and 31°35′ N with the minimum erosion values of 1.11 m2, maximum of 6,044,951.64 m2 and total of 16.02 km2. On the other hand, 177 sites showed minimum accretion values of 0.05 m2, maximum of 2,876,855.86 m2 and total of 13.19 km2. SLR was determined by applying the quadrant equation for 10-year intervals using 1990 as the base year. Mediterranean SLR along the Nile Delta coast could be estimated considering three different scenarios (low 0.20 m, medium 0.50 m, and high 0.90 m). Impacts of SLR are divided into (1) primary and (2) secondary impacts. Over the coming decades, the Nile Delta will face greater threat due to SLR and land subsidence as well. Regarding climate change and its impacts on soil characteristics, rapid increase in salinity values during the former three decades were found. This increase may be due to the intrusion of salty water of the Mediterranean. On the other hand, organic matter content decreased due to higher temperature, especially during the summer season. Some protection measures were assessed and suggested to combat or tackle SLR.

The Nile Delta coast is a dynamic sedimentary environment experiencing erosion, transport and re-deposition of sand along the coast. The aim of this study was to investigate the effectiveness of using an integrated approach of natural radioactivity of coastal sediments, heavy mineral distribution and grain size information to differentiate between the eroding and accreting areas of the Nile Delta coast. Also, it is to investigate the relationship between grain size and heavy mineral distributions of these sediments on the spatial distribution of the coastal radioactive materials. The relatively higher profile averages of 226Ra, 214Pb, 214Bi and 210Pb (as 238U series) were 104.37±84.66, 45.60±37.83, 38.43±32.49 and 35.69±24.86 Bq/kg, respectively and228Ra and 212Pb (as 232Th series) were 54.26±56.66 and 42.18±44.66 Bq/kg, respectively. The highest average value of 40K concentration (404.49±125.81 Bq/kg) was detected in the profile located at 2000.1 m west of Rashid estuary. Microscopic study revealed that the more dominant heavy minerals assemblages consisted of Opaques, Hornblende, Augite, Epidote, Biotite and Chlorite. Also, minor amounts of Garnet, Zircon, Rutile, Tourmaline, Kyanite and Monazite have been identified. Relatively high concentrations of 238U and 232Th series members were found in coincident at sites having higher heavy minerals percentages and detected at erosional beach than the accretion one. Coincidence was recognized between the average concentrations of40K and the percentages of the light minerals collected at 100 m distances of the profiles under investigation. Key words: Nile Delta, beach erosion, beach accretion, natural radioactivity, heavy minerals.

Nonnative, invasive plants are becoming increasingly widespread and abundant throughout the southwestern United States, leading to altered fire regimes and negative effects on native plant communities. Models of potential invasion are pertinent tools for informing regional management. However, most modeling studies have relied on occurrence data, which predict the potential for nonnative establishment only and can overestimate potential risk. We compiled locations of presence and high abundance for two problematic, invasive plants across the southwestern United States: red brome (Bromus rubens L.) and African mustard (Brassica tournefortii Gouan). Using an ensemble of five climate projections and two types of distribution model (MaxEnt and Bioclim), we modeled current and future climatic suitability for establishment of both species. We also used point locations of abundant infestations to model current and future climatic suitability for abundance (i.e., impact niche) of both species. Because interpretations of future ensemble models depend on the threshold used to delineate climatically suitable from unsuitable areas, we applied a low threshold (1 model of 10) and a high threshold (6 or more models of 10). Using the more-conservative high threshold, suitability for Bromus rubens presence expands by 12%, but high abundance contracts by 42%, whereas suitability for Brassica tournefortii presence and high abundance contract by 34% and 56%, respectively. Based on the low threshold (worst-case scenario), suitability for Bromus rubens presence and high abundance are projected to expand by 65% and 64%, respectively, whereas suitability for Brassica tournefortii presence and high abundance expand by 29% and 28%, respectively. The difference between results obtained from the high and low thresholds is indicative of the variability in climate models for this region but can serve as indicators of best- and worst-case scenarios.

Brassica tournefortii Gouan, commonly known (Aslooz) in Tunisia, is an annual plant, native to the North Africa and Middle East. Brassica species are used as food, their young leaves can be cooked, providing nutrients and health-giving phytochemicals such as phenolic compounds, polyphenols and carotenoids. Phytochemical composition and bioactivity of Brassica tournefortii leaf extracts, collected from four different bioclimatic zones in Tunisia, are investigated in the present study. Results showed that location and climatic variations can alter the phytochemical composition of B. tournefortii. Interestingly, HPLC analysis enabled identifying lutein and beta-carotene at high concentrations, especially in extracts of B. tournefortii collected from Gabes (B2) (344 µg/g of lutein) and B. tournefortii collected from Zarzis (B3) (1364 µg/g of beta-carotene). In particular, the antioxidant activity measured by DPPH assay showed that the extract of the plants collected from the growing region of Zarzis exhibits the highest antioxidant activities (0.99 mg/mL). All the Brassica tournefortii extracts showed a relevant antiproliferative activity, especially toward the Caco-2 cell line. These preliminary data resulted in being useful to correlate growth environmental conditions with different accumulation of metabolites in Brassica species still being poorly studied.

Weeds from Brassicaceae family are a major threat in many crops including canola, chickpea, cotton and wheat. Rapistrum rugosum (L) All. and Brassica tournefortii Gouan. are two troublesome weeds in the northern region of Australia. In order to examine their phenology of these weeds, a pot study was conducted in 2018 at the Research Farm of the University of Queensland, Gatton campus with two populations sourced from high (Gatton) and medium (St George) rainfall areas of the northern grain region of Australia. Planting was carried out monthly from April to September, and the growth, flowering and seed production were evaluated. Maximum growth and seed production were observed in weeds planted in April, compared to other planting dates. Biomass of R. rugosum and B. tournefortii was reduced by 85% and 78%, respectively, as a result of the delay in planting from April to July. R. rugosum and B. tournefortii produced more than 13,000 and 3500 seeds plant−1, respectively, when planted in April and seed production was reduced by > 84% and > 76% when planted in July. No significant differences were observed between populations of both weeds for plant height, number of leaves and biomass, however, the medium rainfall population of R. rugosum produced more seeds than the high rainfall population when planted in April. The results of this study suggest that, although R. rugosum and B. tournefortii were able to emerge in a wider time frame, the growth and seed production were greatest when both weeds were planted in April and there was concomitant reduction in growth attributes when planted in the subsequent months, indicating that management of these weeds early in the cropping season is a prerequisite to population reduction and the mitigation of crop yield losses.

African mustard (Brassica tournefortii Gouan) is a problematic winter annual weed in Australia. Germination ecology of B. tournefortii may change in response to the maternal environments or habitats in which the plants grow. A study was conducted to evaluate the effect of environmental factors on germination and emergence of four populations of B. tournefortii that were collected from different fields. Averaged over populations, germination was stimulated by dark and was higher at 25/15 C (92%) compared with 15/5 C (76%) and 35/25 C (45%). Averaged over light/dark regimes, at the lowest temperature regime (15/5 C), population A had higher germination than population D; however, at the highest temperature regime (35/25 C), population D had higher germination than population A. Populations B and C had higher germination in the temperature range of 25/15 C and 30/20 C compared with 15/5 C, 20/10 C, and 35/25 C. Seeds germinated at a wide range of alternating day/night temperatures (15/5 to 35/25 C), suggesting that seeds can germinate throughout the year if other optimum conditions are available. Population A was more tolerant to water and salt stress than population D. The sodium chloride concentration and osmotic potential required to inhibit 50% germination of population A were 68 mM and −0.60 MPa, respectively. Averaged over populations, seeds placed at 1-cm soil depth had the highest emergence (54%), and burial depth of 8 cm resulted in 28% seedling emergence. Averaged over populations, wheat residue retention at 6,000 kg ha−1 resulted in greater seedling emergence than the residue amount of 1,000 kg ha−1. The results suggest that B. tournefortii will be favored in no-till systems and that the seedbank of B. tournefortii could be managed by tillage regimes that bury its seeds below 8-cm depths and restrict seedling emergence and growth of new plants.

The present study aimed to identify the communities with Brassica tournefortii Gouan in Al-Jouf areas in northern Saudi Arabia, to determine the ecological amplitude of this species and soil factors controlling its distribution. The plant communities dominated by B. tournefortii were investigated in fifteen localities through 15 plots. In each plot the present species were recorded. Data were treated by multivariate analyses. Soils of each community were analyzed using eleven physico-chemical parameters. Analysis of variance and correlation coefficient were performed based on R software package. Three vegetation types have been recognized by the applications of Past program classification. 83 species have been observed. Canonical correspondence analysis demonstrated that soil parameters contributed significantly to the distribution of species. B. tournefortii dominated the communities in newly reclaimed lands, where it survived in sandy habitats. It is characterized by high competition with both cultivated plants and associated weeds. This paper represents a study of the diversity of B. tournefortii communities in Arabia Saudi.

Some proposals for coastal management of the Nile delta coast

The Nile Delta is located very close to the Suez Canal, the main route for oil transport in the world, makes it prone to pollution from any accidental oil spills in the Mediterranean Sea. The coast of the Nile Delta is generally arcuate and highly exposed to waves and currents. The present study attempted to perform the environmental sensitivity of the shoreline to oil slicks. Six variables were incorporated together in order to determine the environmental sensitivity index (ESI). Data were collected from different resources and from in situ observations. Results showed that the ESI is generally high for the western section of the Nile Delta, particularly along Alexandria region. Low ESI was observed along the shorelines facing the coastal sand dunes at the middle part of the delta coast. The ESI is an effective approach to delineate the vulnerable coastal areas to marine oil pollution.

For calculating subsidence rates along the Nile Delta coastal margin, archaeological site data provide more accurate temporal and elevation control relative to Holocene sea levels than chronostratigraphic analyses of radiocarbon-dated sediment cores. Recently acquired data on the depth and age of 11 buried and/or submerged levels of human activity at seven ancient sites serve to calculate average annual rates of subsidence along the northern Nile Delta margin during the middle to late Holocene. Subsidence rates range from 0.9 to 4.3 mm/yr, varying irregularly from west to east along the northern delta coast, and averaging ∼2.5 mm/yr for 11 data points on the margin as a whole. Subsidence rate is directly related to thickness of sediment section, with highest values in the eastern part of Manzala lagoon and at coastal promontories of the Damietta and Rosetta branches. This, in large part, is a function of underlying sediment compaction plus sediment loading and readjustment of strata at depth. Sho...

Summary Costal soil characterization has a great significance in environmental and engineering studies. The present work is a proposed protocol using remote sensing (RS), direct current resistivity (DCR) and time-domain induced polarization (TDIP) data for characterizing the coastal soil on the Nile Delta coast. The land use-land cover (LU-LC) is introduced to get the changes in land degradation over the selected analysis period. Considering RS data analysis, geoelectrical measurements are carried out. Regarding to the saltwater intrusion and other heavy anthropogenic activities along the coastal zones, it can be noticed that the lateral heterogeneities within the near-surface coastal soil cannot be characterized using individual DCR data. The 2D resistivity profiles show limitations in mapping the high conductive layers of smearing and amplification of the conductive layer boundaries. On the other hand, the 2D-TDIP images can differentiate between the high conductive layer and saltwater intrusion calibrating with the nearby borehole data. Interestingly, negative chargeability data has been reported for coastal clays. Finally, the electric cone penetration test (CPT) with pore pressure measurements is carried out to confirm and calibrate the geophysical inversion results. The success of the proposed approach supports further studies into understating the geotechnical properties in such coastal areas.

Twenty-four sediment samples were collected from six coastal areas along the Nile Delta coast, including Abu Qir Bay, Rosetta estuary, Abu Khashaba, El Burullus fishing port, El Gamil inlet and Damietta Harbor. Environmental parameters such as grain size, total organic matter, calcium carbonate and seven heavy metals concentration have been investigated. Seventy-two foraminiferal species were identified and counted. The study area has low foraminiferal density but diversified foraminiferal assemblages. Q-mode and R-mode cluster analyses have been applied to assess the relationship between foraminiferal assemblages and the measured environmental factors. Different diversity indices [e.g., species richness (S), Shannon index, Simpson index, Fisher alpha index, and Dominance] have been examined. The statistical results allowed the recognition of different species assemblages corresponding to different sub-environments, which reflected the prevalent ecological and pollution conditions. There are two main recognized clusters dividing the sampling stations into less polluted cluster (A) at El Burullus fishing port, El Gamil inlet and Abu Khashaba and highly polluted cluster (B) at Abu Qir Bay and Damietta Harbor. Ammonia tepida, Ammonia beccarii, Triloculina trigonula, Quinqueloculina lata, and Quinqueloculina spp. are recognized as pollution tolerant species, while Ammonia parkinsoniana, Porosononion spp., Buccella spp., Ammonia spp., and Ammonia sp1 are recognized as pollution-sensitive species. A high percentage of deformed specimens was recorded in the polluted areas especially in Damietta Harbor.

Nile delta: extreme case of sediment entrapment on a delta plain and consequent coastal land loss