جستجوی مقالات مرتبط با کلیدواژه "زی توده" در نشریات گروه "محیط زیست"

Urban is a unique and inconsistently defined land cover including green and grey infrastructures. Tree covers that can store large stocks of carbon. There are several ways to estimate a tree's CO2 sequestration. In this study, Google Earth images were used for mapping tree covers in the Hamadan urban scale with an area of 7422 hectares. First, a 50-meter buffer was applied on two sides of the main streets. Then, it was classified into three groups called high, medium, and low density based on the percentage of greenery. In each group, the information of 265 trees (the total of 800 trees) were recorded randomly such as allometric data and canopy diameter of trees. An Object-Oriented approach was applied to extract the area and canopies of individual urban trees. The total number of trees and their location were estimated by dividing the total of trees canopy by the average of the individual urban trees canopy. Allometric equations were used to estimate the dry biomass of tree species. Based on the results, the main species in the study area include maple, black locust, sycamore, manna ash, cypress, fir tree, and elm. The average amount of organic carbon stored in individual and street trees with asphalt and cobblestone pavement is estimated to be about 88.29 kg, which differs significantly from those with the surface covered by soil and grass (an average value of 148.79 kg). In total, the amount of organic carbon stored by Hamadan urban trees is estimated to be 1.6 tons per hectare.

This research was carried out based on ecological monitoring of the Caspian Sea in depth of 30 meters project during 2018-2019. Sampling from the bed sediments of the southern Caspian Sea in 8 transects including Astara, Anzali, Sefidrood, Tonekabon, Nowshahr, Babolsar, Amirabad and Turkmen was done by a cat sampler. Sampling was done seasonally. The aim of this study was to investigate the species diversity, density and biomass and local distribution of different macrobenthos species. A total of 16 species were identified, belonging to 7 families which of Polychaeta, Crustacea and Bivalvia were found. In addition, Oligochaeta have been identified. The polychaeta comprised 59% of the total macrobenthos density. In contrast, Cerastoderma glaucum, although the frequency was 6.3% of the total density of macrobenthos, but comprised 59.9% of the total biomass. The results showed that the diversity indices had the highest value in spring and the lowest in summer. Polychaeta had the highest local distribution (100%) and Malacostraca Pterocuma sowinskyi and Cardiophila baeri had the lowest (8.2%). The lowest and highest mean (±SE) densities were recorded in winter and spring with 408±81.1 ind.m-2 and 1225±246.2 ind.m-2, respectively. In conclusion, the increase in biomass of bivalve molluscs versus the decrease in density can be due to the large size and having oyster shell and the increase in diversity indices in spring can be due to the presence of different species for reproduction after wintering period which is consistent with the density of macrobenthos in the spring.

This study done in the Spring, Summer, Autumn and Winter, at 40 study sites from 8 transect between Astara to border of Hasangholipour. Transect are in Astara, Bandar Anzali, Sefidrood, Tonekabon, Noshahr, Babolsar, Amirabad, Bandar Turkman and the SouthCoast of the Caspian Sea. In each transect, 5 stations at depths of 5 m, 10 m, 20 m, 50 m and 100 m were determined to sample a chapter of depth zero (level) and 10 m, 20 m, 50 m and 100 m by Rutner was performed. A total of 24 species were identified from the phylum Dinoflagella. The maximum density Dinoflagella (28.17 ± 27.14 per cubic meter × 106) and maximum biomass 349 ± 336 mg per cubic meter, respectively. Most species diversity Dinoflagella phylum in winter (17 species) has been that species Exuviaella cordata، Goniaulax polyedra، Peridinium achromaticum، Peridinium latum،  Prorocentrum praximum و Prorocentrum scutllum   were observed in all seasons. Phylum Dinoflagella with an average density of 28/17 ± 27/14 (the number of cubic meters × 106) and the average biomass annually 349 ± 336 (milligrams per cubic meter) of approximately 9% density and 4% biomass phytoplankton of area in the country.The diversity, the density and biomass Dinoflagella have been significant changes (p<0.05).Ongoing changes in microscopic plants including Dinoflagella can effect on fish migration patterns, their growth rate, mortality rate and of course the critical gas concentrations in the atmosphere.

Sepia pharaonis and Trichiurus lepturus are two species target catch of Bottom Trawl. These two species because of the value of export and money are very important economically. This study Biomass and the mean Catch per Unit of Area (CPUA) Sepia pharaonis and Trichiurus lepturus of Bottom Trawl fisheryfrom Oman Sea (Sistan and Balochestan province coastal waters) were investigated. Data were collected in one research cruise by using R/V Ferdows-1 during September and October 2016. The study area was stratified into 5 strata (M to Q) and 4 Substratum covering the depths of 10-20, 20-30, 30-50 and 50-100 m in the Oman Sea. A total of 92 stations were randomly selected and the biomass and CPUA were estimated by swept area method. Result indicated that maximum and minimum the mean CPUA of Sepia pharaonis was 894.0 Kg.nm-2 and 64.1 Kg.nm-2 in the region M and Q respectively. Maximum and minimum the mean CPUA of Trichiurus lepturus was 2485.3 Kg.nm-2 and 49.9 Kg.nm-2 in the region N and Q respectively. Maximum and minimum biomass of Sepia pharaonis was estimated 240.3 tons and 46.6 ton in the region P and Q respectively. Maximum and minimum biomass of Trichiurus lepturus was estimated 899.3 ton and 21.7 tons in the region N and M respectively. Also maximum and minimum the mean CPUA and biomass of Sepia pharaonis and Trichiurus lepturus were obtained in depth of 50-100 m and 10-20 m respectively. Result this study is useful for management of these two species resources from of Oman Sea.

Nowadays, the environmental impact of fish culture on water quality and benthic macroinvertebrates is known as pollution water. Therefore the studies were carried out to determinate of distribution, abundance and biomass value macro invertebrate around Sturgeon pen culture in Gorgan Gulf. Seasonal samplings were carried out from August 2015 to July 2016. The study was done at 5 stations in 3 transects, where three pen culture were active. Stations were in distance 0, 5, 25, 50 and 100 m far from pen. Benthos was collected using a van Veen grab (20*25 cm). Density, abundance percent and biomass were calculated for groups. Totally, 11 genus's and 10 families belong to 3 phyla as Mollusks, Arthropods and Annelids were identified. The results showed, there were the maximum abundance percent belong to Pyrgulidae (Hydrobiidae) and Cochliopidae with 33.83% and 26.05% and the minimum abundance percent belong to Gammaridae with 0.05% respectively. However, the maximum abundance belongs to Pyrgohydrobia sp., from Pyrgulidae with 3410 n/m2. The results showed, there were the maximum and minimum abundance in autumn and spring with 3263n and 2044n respectively. So, there were the maximum and minimum abundance of benthic in 3 and 1 stations with 2469 n and 1821 n respectively. Finally, there were no significant difference on abundance and biomass macroinvertebrate around Sturgeon pen culture in Gorgan Gulf (p>0.05).

Accurate estimation of forest biomass for assessment of the potential of forests to sequester atmospheric carbon is an important aspect in forest management. The present study aimed to estimate the biomass of single-stem Quercus brantii trees by using terrestrial photogrammetry as a nondestructive method.
The study was conducted in Chaharmahal and Bakhtiari province. First, 32 individual trees from different diameter classes were selected and two photos were taken for each tree in perpendicular directions. Then, the scale of each photo was calculated and the volume of different components of trees was determined (trunk, main branches, branches and foliage (Crown)). Density of each component was measured using data collected from field and laboratory analysis; and biomass of each component was measured. Estimated biomass from terrestrial photogrammetry method was compared with the actual biomass obtained from the field method.
Findings: Results showed that there is no significant difference between the terrestrial photogrammetry method and the field method, which is accurate method in order to evaluate biomass.
Discussion and This study showed that terrestrial photogrammetry for estimation of above ground biomass for single-stem Quercus brantii trees is an accurate and efficient method.

Rangelands ecosystems have a large potential to sequester C because they occupy about half of the world's land area. This study investigate the role of Atriplex canescens in carbon sequestration in rangeland research station of Cheshmeh Ali in Qazvin province. Main treatment applied in a split plot design using randomized completely blocks included two densities, 2×2 m and 4×4 m. In each treatment, four pruning height included without pruning (control treatment), completely pruning, pruning in 20cm and 40cm above ground. Carbon amount were measured for above and underground biomass and soil in density and pruning height separately. Results showed that mean carbon in above and underground biomass per area unit in 2×2m treatment are higher than 4×4m treatment significantly. In 2×2m spacing, the total carbon amount of total biomass (2370 kg/ha) was twice as much amount as 4×4m treatment did significant difference was observed in total sequestrated carbon in plant spacing and purning height treatment. Mean total carbon sequestration per hectar were 59/16 and 59/81 ton in 2×2m and 4×4m treatment. Corolation analysis indicated that there is significant and positive relationship between total sequestrated carbon and organic carbon. Therefore the results suggest that good management practices in rangelands result in increased carbon storage and can increases carbon sequestration.

Mediterranean Cypress (Cupressus sempervirens var. fastigiata) is a native, evergreen species. Due to its various merits, particularly its wide use in parks and urban green spaces, it is of interest in most climatic regions of Iran, including Zagros provinces. Due to the poverty of soil and limitation in water sources, the production of seedlings of this species has become particularly problematic in some of these regions. By using rhizobacteria Pseudomonas fluorescens inoculation in soil, for the first time, the present study aims to determine the resistance and variations of growth characteristics of seedlings under water deficit conditions. The experiment was conducted as a factorial, using a completely randomized design with two treatments (i.e., with rhizobacteria and without rhizobacteria), different watering levels (3, 6, 9 and 12 days) in three replicates. After 5 months, growth characteristics of seedlings were measured. Increasing the watering period (water deficit) caused to significantly decrease the survival, diameter, shoot biomass and total biomass, so that all seedlings were died under 12-day watering level. In watering period of 9 days, survival was reduced to 49.83 percent. There was no significant difference in collar diameter, root length, root volume and root/shoot biomass with water deficit intensity. However, the survival rate, height growth, shoot biomass, root biomass, total biomass and seedling quality index were greater in seedlings inoculated with rhizobacteria, compared with those of non-inoculated seedlings. The seedlings of Mediterranean Cypress inoculated with Pseudomonas fluorescens rhizobacteria are able to tolerate the water deficit stress and increase their growth performance; however, under optimal conditions, the rhizobacteria inoculation has no positive effect on survival rate of the seedlings.

To compare physical, chemical and biological indices of primary productions on the coast of Bandar-e Anzali, water column in the depths of 2, 5 and 10 meters was sampled. The physical index of primary productions by using the Secchi disc Was calculated, chemical index by measuring the density of nutrients in water and biological index by determining the density of Chlorophyll a in phytoplankton’s were calculated. The maximum clearance was 300 centimeters in spring and the average maximum density of total Phosphorus and total Nitrogen in water column was in spring and respectively 0.061 and 0.831 milligram per Liter (p<0.05). The maximum density of Chlorophyll a was in summer, 6.4 microgram per cubic meter. The results show that among these indices, it is better to use physical and biological indices. Both indices statistically have reversed correlation (p<0.05). Through comparison of information with qualitative water class tables, water of Caspian Sea can be located in Mesotroph water class from the density of Chlorophyll a point of view according to the amount of summer vision depth by Secchi disc and at the beginning of Eutroph water class from the point of view of total Phosphorus and total Nitrogen (p<0.05).

Greenhouse effect is one of the most severe current environmental problems. Forest ecosystems with their complex structure and function can play an important role in mitigating the emissions of CO2 as the most important greenhouse gas. Forest biomass and soil can be considered as the sinks of carbon. Many factors such as canopy cover percentage, forest type and species diversity, of species age structure, environmental conditions, and forest management methods affect the carbon sequestration. In this study, carbon sequestration in soil and plant biomass in pure and mixed beech stands of Gorazbon district in Kheyrud forests was estimated and valued.The amount of carbon stored in forest tree foliage and ground was estimated using the photosynthesis formula and the sequestration of carbon in mineral and organic soil horizons was determined using experimental methods, Walkly–black and oven respectively. The results showed that there is a significant difference between amount of carbon sequestration by the mixed and pure beech stands in both plant and soil biomass and the pure stand stores more CO2 than mixed one. Finally, the economic value of carbon sequestration function was estimated using cost avoided damage method. The results revealed that the average value of pure beech stand is 9.5 million Rials ($ 320) and 8.3 million Rials ($ 275) ha/year respectively, in terms of carbon sequestration function.

The term ‘‘marine fouling’’ is generally applied to the assemblages of marine organisms that colonize artificial rather than natural substrate. Barnacles (Crustacea) are a dominant component of animal fouling species on artificial and natural substrates, as they are best adapted to sessile way of life. The purpose of this study was to determined deployment recruitment Balanus amphitrite on constructions in the Imam Khomeini Port. To achieve the aims of present research, concrete panels (20 × 30 cm) were designed and installed at depth 3 and 10 meter under seawater level in 4 stations. Panels were collected after 2 months and transferred to the laboratory for further investigations. The results indicated that the B. amphitrite recruitment occurred throughout the year with varying intensities. Maximum biomass of 1943.49 ± 13.74 g.m2 was observed during April 2010 and a minimum value of 4.31± 1.22gr.m2 in February 2009.