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1.
Coastal zones around the world have experienced urban growth in the last 50 years. This landscape change brings new aspects for those zones and the environment. Real estate speculation is a decisive factor that changes landscape, with urban growth that occurs both in the extent and volume of construction. Boa Viagem (BV) beach at Recife, Northeast Brazil was just a sand bar covered by an Atlantic Forest until middle of the 1800s. Today, it has turned into a busy area of the city where residences, services and commerce co-exist in a densely packed arrangement. This work demonstrates and analyses vertical growth in BV and urban changes from 1961 to 2011. It was developed using digital image processing and visual analysis of satellite imagery and aerial photos. A GIS was created using SPRING and ArcScene, to calculate variations in area and volume creating a Volumetric Index (VI). The Minimal Mapping Area was used in sixteen census tract as samples of the area. Occupation and vertical growth were especially accentuated from 1981 to 1996 with the peak at 2011. Increases in vertical growth from shore to inland are evident in all parts of the district. This finding was confirmed by three-dimensional GIS representations of the study area and the VI during the period of this work, showing the potential of 3D GIS models for studying dense urbanization areas in coastal zones.  相似文献   

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3.
Given the excessive use pressure on forests, characterisation of the major users of forest resources can help guide conservation efforts. This study examines whether socio-economic variables explain domestic wood use in an area of Atlantic forest in the community of Três Ladeiras (Pernambuco, north-east Brazil). Socio-economic data were collected from 62 households, and geometric measurements of wood products in each household were taken to calculate the wood volume. An informant in each household indicated the average replacement time for each type of wood use. Data were analysed for static volume (wood volume found at the time of the visit) and dynamic volume (rate of wood consumption, calculated as the ratio between volume and replacement time). Multiple regression analyses were performed to determine the relationships between wood volume (static and dynamic) and the number of species used; independent variables including monthly family income, number of residents, average age of heads of the household, age of oldest household member, average residence time of heads of the household, average education level of heads of the household and education level of the most educated household member. Monthly income was inversely related to the static wood volume (adjusted R 2 = 17.6%, p < 0.001), rate of wood consumption (adjusted R 2 = 23.0%, p < 0.001) and number of species used (adjusted R 2 = 22.3%, p < 0.001) and was the most important predictive variable for these three outcomes. Other factors such as average education level and average age of heads of the household were also explanatory variables of the total rate of wood consumption, as these two variables, together with monthly family income, explain 31.3% of the total dynamic volume. Given the high importance of income in our study, we suggest that future conservation strategies give special attention to the poorest members of the community.  相似文献   

4.
Reproduction of Asterina stellifera was studied in two populations from the Cabo Frio region, southeastern Brazil. One was located in an intertidal seagrass flat at Japonês Island (1994–1995); the second was on a sublittoral rocky shore at Pontal beaches (1999–2000). Reproductive cycle was studied at monthly intervals by organ indices and histological examinations of gonads. Although these two populations were studied in different habitats and at different times, the periodicity of the annual reproductive cycle was very similar for the two populations. The highest gonad index (GI) values were found in August/September (late winter), followed by a drop in GI values, indicating spawning. The GI and pyloric caeca index (PCI) tended to have an inverse relationship in both populations, but it was only statistically significant in the rocky-shore population. Gametogenesis in the two populations was described and roughly confirmed the reproductive cycles determined by GIs. Published online: 9 August 2002  相似文献   

5.
The Pialassa Baiona is an intertidal lagoon located north from the town of Ravenna (Italy). It shows a certain degree of contamination caused by past uncontrolled discharges, and we aim at developing a bioassessment program to be used for future monitoring and conservation plans. A battery of six biomarkers (lysosome membrane stability, lipofuscin and neutral lipid accumulation, hsp70 expression, metallothionein levels and acetylcholinesterase (AChE) activity) was investigated in Mytilus galloprovincialis transplanted for 30 days in different sites. Tapes philippinarum are widely distributed within the lagoon, and we explored the possibility to use resident clams for future biosurveillance programs. Adenylyl cyclase (ACase) activity was also assessed in tissues of both bivalves as a future possible biomarker. Taken together, our results indicate that mussels are suitable sentinel organisms also within such a peculiar environment; alteration of four biomarkers was observed in tissues of mussels transplanted in two sites out of the five analyzed, indicating their low water quality. T. philippinarum showed a barely detectable AChE activity and absence of neutral lipids in digestive glands, therefore appeared unsuitable for our purpose, at least using the selected battery of biomarkers. ACase activity was not different among animals collected from the different sites.  相似文献   

6.
Novel approaches to control invasive species are urgently needed. Cane toads (Bufo marinus) are large, highly toxic anurans that are spreading rapidly through tropical Australia. Injured toad larvae produce an alarm pheromone that elicits rapid avoidance by conspecifics but not by frog larvae. Experiments in outdoor ponds show that repeated exposure to the pheromone reduced toad tadpole survival rates (by >50%) and body mass at metamorphosis (by 20%). The alarm pheromone did not induce tadpoles to seek shelter, but accelerated ontogenetic differentiation. Perhaps reflecting mortality of weaker individuals during larval life, growth rates post-metamorphosis were higher in animals emerging from the pheromone exposure treatment than from the control treatment. Nonetheless, body size differentials established at metamorphosis persisted through the first 8 days of post-metamorphic life. We will need substantial additional research before evaluating whether the alarm pheromone provides a way to reduce cane toad recruitment in nature, but our field trials are encouraging in this respect.  相似文献   

7.
Rain precipitation in the last years has been very atypical in different regions of the world, possibly, due to climate changes. We analyze Standard Precipitation Index (SPI) measures (1, 3, 6 and 12-month timescales) for a large city in Brazil: Campinas located in the southeast region of Brazil, São Paulo State, ranging from January 01, 1947 to May 01, 2011. A Bayesian analysis of non-homogeneous Poisson processes in presence or not of change-points is developed using Markov Chain Monte Carlo methods in the data analysis. We consider a special class of models: the power law process. We also discuss some discrimination methods for the choice of the better model to be used for the rain precipitation data.  相似文献   

8.
The performance of an artificial practical diet, kappacarrageenan microbound diet (C-MBD) was assessed on Penaeus monodon larvae at the SEAFDEC Broodstock and Maturation Experimental Laboratory in March 1986. Shrimps were reared from zoea1 to post-larvae1 using five dietary treatments: (a) natural food — Chaetoceros calicitrans and Artemia salina (b) C-MBD; (c) combination of natural food and C-MBD; (d) commercial diet (microencapsulated, MED); (e) combination of natural food and commercial diet. Results showed slow development with larvae fed the commercial diet. Feeding with C-MBD in combination with natural food resulted in the highest % survival among treatments (69.6), but this was not significantly different (P>0.05) from those obtained with larvae fed natural food alone, C-MBD alone or their combination. While mean values for survival of larvae fed the commercial diet, either alone or in combination, was significantly lower (p<0.05) than all other treatments, their mean growth indices were comparable with larvae fed C-MBD alone or in combination. The low levels of protein, lipid and essentially fatty acids (which are considered important nutrients during larval development) contained in the commercial diet may well justify the results on metamorphosis, survival and growth of the larvae fed this diet. The good performance of C-MBD in this experiment suggests that this kind of diet can be used as partial or total replacement to the traditional algal food.  相似文献   

9.
This study employed polyphasic chlorophyll a fluorescence transients (OJIP), a non-invasive marker of environmental stress in plants, to evaluate salt tolerance in three different Juncus roemerianus age classifications (6-, 24-, and 60-months). Following exposure to elevated salts (30 psu), the younger plants sustained growth, which was comparable to freshwater controls. While older (60-month) plants receiving only freshwater also grew over the 8-week study, the older salt-treated plants did not increase in size. Similarly, there were significant declines in variable chlorophyll a fluorescence parameters (F v/F m and F v/F o), electron transport flux per reaction center (ETo/RC), and photosystem II performance index (PIABS) for 60-month J. roemerianus following salt treatment. These responses were not evident in the two younger salt-treated age classifications. Our results suggest that older J. roemerianus are less tolerant to rapid and sudden increases in salinity relative to younger plants and that this age-specific response may help explain observed discrepancies in salt tolerance in J. roemerianus.  相似文献   

10.
An approach combining nutrient budgets, dynamic modelling, and field observations of phytoplankton and nitrogen (N2)-fixing Lyngbya majuscula following changes in wastewater N loads, was used to demonstrate that Moreton Bay is potentially phosphorus (P) limited. Modelling and nutrient budgeting shows that benthic N-fixation loads are high, allowing the system to overcome any potential N-limitation. Phytoplankton biomass has shown little change from 1991 to 2006 in the sections of Moreton Bay most impacted by wastewater effluents, despite a large reduction in wastewater N loads from 2000 to 2002. This is consistent with modelling that also showed no reduction in primary productivity associated with reduced N loads. Most importantly, there have been rapid increases in the occurrence of N-fixing L. majuscula in Moreton Bay as wastewater P loads have increased relative to wastewater N loads. This is also consistent with modelling. This work supports the premise that there may be fundamental differences in nutrient limitation of primary production between subtropical and temperate coastal systems due to differences in the importance of internal nitrogen sources and sinks (N-fixation and denitrification). These differences need to be recognised for optimum management of coastal systems.  相似文献   

11.
The effects of thinning on mineral soil and forest floor for three different thinning intensities (control, moderate and heavy) were studied in a sessile oak forest 8 years after treatment. To examine responses to thinning, mass, organic matter and total nitrogen content in forest floor, bulk density and fine soil weight, total nitrogen, organic carbon concentrations and pH in upper mineral soil horizons were measured, and the results compared to control plot. The thinned plots have shown higher total nitrogen concentration and organic carbon in soil. Total mass, weight of layers of forest floor have shown significant patterns with thinning intensity. The present results indicate that various intensities of thinning for a sessile oak stand had major influence on soil and forest floor in eight years following treatment.  相似文献   

12.
Considering the current poor understanding of the seawater–freshwater (SW–FW) interaction pattern at dynamic hydro-geological boundary of coastal aquifers, this work strives to study tidal effect on groundwater quality using chemical tracers combined with environmental isotopes. In situ measurement data of electrical conductivity and groundwater level along with laboratory measurement data of hydro-chemical species were compared with tidal level data measured by Hydrographic and Oceanographic Department, Saijo City, Japan for time series analysis. Result shows that diurnal tides have significant effect on groundwater level as well as its chemical characteristics; however, the magnitude of effect is different in case of different aquifers. Various scatter diagrams were plotted in order to infer mechanisms responsible for water quality change with tidal phase, and results show that cations exchange, selective movement and local SW–FW mixing were likely to be the main processes responsible for water quality changes. It was also found that geological structure of the aquifers is the most important factor affecting the intensity of tidal effect on water quality.  相似文献   

13.
Most rapidly changing areas are beset by intensified conflicts of use, where the environmental dimension plays an increasingly important role. These antagonistic situations represent a challenge for continuing and launching territorial public actions for integrated resource management. This contribution aims to highlight the socio-spatial dynamics of conflicts of use relating to the environment and provides methodological elements to characterise the conflictual processes at work in rapidly changing areas. It sets out elements of research on the Languedoc-Roussillon coastal zone, based on the hypothesis that sustainable management of territories’ gains by being acquainted with conflict mechanisms (the emergence factor, modes of dissent, methods of regulation) and the actors involved (role, organisation, strategies), in time and in space. An interpretative framework for the conflictual processes relating to the environment is proposed, in order to provide a complementary analysis of the typologies of existing conflicts.  相似文献   

14.
Geochemical analyses using a sequential extraction method and lead adsorption studies were carried out in order to characterize the distribution and adsorption of lead on each genetic horizon of a Luvisol profile developed on a pelagic clayey aleurolite. Clay illuviation is the most important pedogenic process in the profile studied. Its clay mineralogy is characterized by chlorite/vermiculite species with increasing chlorite component downward. The amount of carbonate minerals strongly increases in the lower part of the profile resulting in an abrupt rise in soil pH within a small distance. The Pb content of the soil profile exceeds the natural geochemical background only in the Ao horizon, and its amount decreases with depth in the profile without correcting for differences in bulk density, suggesting the binding of Pb to soil organic matter. According to the sequential extraction analysis the organic matter and carbonate content of the soil have the most significant effect on lead distribution. This effect varies in the different soil horizons. Lead adsorption experiments were carried out on whole soil samples, soil clay fractions, as well as on their carbonate and organic matter free variant. The different soil horizons adsorb lead to different extents depending on their organic matter, clay mineral and carbonate content; and the mineralogical features of soil clays significantly affect their lead adsorption capacity. The clay fraction adsorbs 25 more lead than the whole soil, while in the calcareous subsoil a significant proportion of lead is precipitated due to the alkaline conditions. 10 and 5 of adsorbed Pb can be leached with distilled water in the organic matter and clay mineral dominated soil horizons, respectively. These results suggest that soil organic matter plays a decisive role in the adsorption of Pb, but the fixation by clay minerals is stronger.*This study was presented at the 20th European SEGH conference in Debrecen, Hungary, 2002.  相似文献   

15.
The EI-Dabaa area is located on the northwestern coastal zone of Egypt and is considered to be one of the most important regions for land reclamation and agriculture. In addition, it has been selected as a potential site for constructing Egypt's first nuclear power plant.In April 1989, 14 groundwater samples were collected from the area as well as collecting samples from the Mediterranean sea and from local rainwater. These samples were subjected to chemical and environmental isotope analyses. The results of the analyses for stable isotopes (oxygen-18 and deuterium) indicate that the main recharge source of the groundwater in El-Dabaa is the local precipitation during the rainy season. Variation of the environmental tritium content as well as in the chemical composition of both major cations (Na,K,Ca,Mg) and major anions (Cl,SO4,HCO3) between different groundwaters in the studied area reflect the high degree of inhomogeneity of the aquifer and different recharging conditions due to permeability of the water bearing formation.The chemical water type of the El-Dabaa groundwater is sodium sulphate (Na2SO4) and the SAR values illustrate the suitability of these groundwaters for agricultural purposes.  相似文献   

16.
Airborne fluoride was determined in the rainwater, surface soil and groundwater along a gradient of emission of a phosphate fertilizer factory in Rio Grande, southern Brazil. Concentrations of fluoride in rainwater and groundwater achieved 3 mg l−1 and 5 mg l−1, respectively, and were dependent on pH. The fluoride deposited from emissions accumulated in a superficial horizon of soil in quantities comparable to those in the manufactured end-products—up to 23,000 mg kg−1. Fluoride distribution in the environment is controlled by physical–chemical parameters of emission, rain intensity and soil properties. The highest fluoride concentrations were registered at a close distance of up to 2 km from the factory. The distribution of fluoride in groundwater resembled the same distribution in rainwater due to the high permeability of the local soils. Fluoride penetration to the groundwater also depended on the type of vegetation cover. The groundwater in woodland areas was less affected by contamination of fluoride than in the grassland areas, most probably because of the influence of eucalyptus throughfall, which increases the pH of wet precipitates.  相似文献   

17.
Summary. The female of the cockroach, Diploptera punctata, mates immediately after the last molt, when she is still teneral. In this condition, her quinone-producing defensive glands are empty and she is potentially vulnerable to predation. By mating with fully sclerotized males whose glands are functional, she may benefit, indirectly, from the protection provided by the male's own glandular discharges. However, while males do indeed eject their defensive spray when disturbed while mating, and as a rule tend to remain coupled to the female when disturbed, they spray only when they themselves are the target of the offense. Copulating males do not activate their defenses in response to disturbance of the female.  相似文献   

18.
We studied the population dynamics and the reproductive biology of Penilia avirostris during three consecutive years on the inner shelf off Ubatuba, Brazil. Penilia avirostris individuals and its eggs and embryos were counted, measured, and classified into stages. The species occurred throughout the studied period, in a wide temperature range (14.8–28.2°C). Cladoceran densities were usually higher (>2,000 ind m−3) in warm seasons, when the water column was stratified as a consequence of bottom intrusions of the cold- and nutrient-rich South Atlantic Central Water. Juveniles, non-reproducing females, and parthenogenic females were the dominant developmental stages. Males and gamogenic females were rare and only occurred when females reached peak abundances. This suggests that in tropical and subtropical coastal seas gamogenesis in P. avirostris is not as common as in temperate seas, but may play a significant role in the density-dependent control of the population preceding unfavourable periods.  相似文献   

19.
In this study we examine male song output as a measure of nest site quality in blackcaps (Sylvia atricapilla). Song rate, breeding success, predation on nests and reaction to playbacks were investigated in individual males. Habitat features determining nest site and song post quality in terms of vegetation cover were compared between successful nests and nests that had suffered predation. We then related song rate of unmated males to habitat factors in territories and nesting sites in order to examine a possible predictor function of blackcap song for habitat quality. Several habitat features are responsible for variation in nesting success. These features also correlate with song rate of unmated males. The study indicates a potential role of song rate in the advertisement of territory quality. Furthermore, the data suggest that females use song rates rather than territory quality in mating decisions. The information females may gain about male quality in relation to territory quality are also discussed.  相似文献   

20.
Coastal areas of Iran are heavily affected by urbanisation, industrialisation, and maritime activities. One consequence of this environmental pressure is the contaminants accumulation, as heavy metals, into the marine ecosystem. In this review, the coastal areas in the north and south of the country were assessed for lead (Pb) contamination of, one of the most toxic metals found in the environment. All studies conducted during 2006–2016 with at least 10 specimens that reported the mean and standard deviation of Pb were considered in this review. Heterogeneity between studies was assessed using the Q and I2 statistics. The Pb mean concentration overall studies was estimated to be 21.88?µg/g (95% CIs: 16.25–27.50). Random effect model showed no statistical difference in mean Pb concentration levels between south and north coasts. However, the variability in Pb mean concentrations within southern coasts was considerable and statistically significant. Moreover, the Pb concentrations in the northern coasts of Persian Gulf and Oman Sea, in south of Iran, decreased in the following order Hormozgan > Khuzestan > Sistan-VA-Balluchestan > Bushehr while in the southern coasts of Caspian Sea, in north of Iran, decreased in the order Guilan > Mazandaran > Golestan.  相似文献   

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