Driving factors for forest fire occurrence in Durango State of Mexico: A geospatial perspective   总被引：3，自引：2，他引：1  

Diana Avila-Flores  Marin Pompa-Garcia  Xanat Antonio-Nemiga  Dante A Rodriguez-Trejo  Eduardo Vargas-Perez  Javier Santillan-Perez 《中国地理科学(英文版)》2010,20(6):491-497

Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide. Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence. The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango, Mexico. For this purpose, data from forest fire records for a five-year period were analyzed. The spatial correlations between forest fire occurrence and intensity of land use, susceptibility of vegetation, temperature, precipitation and slope were tested by Geographically Weighted Regression (GWR) method, under an Ordinary Least Square estimator. Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use, and land use change is one of the main explanatory variables. In addition, vegetation type and precipitation are also the main driving factors. The fitting model indicates obvious link between the variables. Forest fire was found to be the consequence of a particular combination of the environmental factors, and when these factors coexist with human activities, there is high probability of forest fire occurrence. Mandatory regulation of human activities is a key strategy for forest fire prevention.  相似文献   

Comparison of the role of two Spartina species in terms of phytostabilization and bioaccumulation of metals in the estuarine sediment     

Cambrollé J  Redondo-Gómez S  Mateos-Naranjo E  Figueroa ME 《Marine pollution bulletin》2008,56(12):2037-2042

In the joint estuary of the Odiel and Tinto rivers (SW Spain), the invasive Spartina densiflora Brongn. and the native Spartina maritima (Curtis) Fernald are growing over sediments with extreme concentrations of heavy metals. The contents of As, Cu, Fe, Mn, Pb and Zn were determined in sediments, rhizosediments and different tissues of both species, from Odiel and Tinto marshes. S. densiflora showed a higher capability to retain metals around their roots and to control the uptake or transport of metals, mediated by a higher formation of plaques of Fe/Mn (hydro) oxides on the roots. At the Tinto marsh, there were no differences between the metal concentrations of the sediment and those of the rhizosediment, a fact that could be explained by the extremely high concentrations of metals which can pass over a threshold value, altering the properties of root cells and preventing roots from acting as a ‘barrier’ to the uptake or transport of metals.  相似文献   

Visible–near infrared spectral indices for mapping mineralogy and chemistry with OSIRIS‐REx     

Hannah H. Kaplan  Victoria E. Hamilton  Ellen S. Howell  F. Scott Anderson  M. Antonella Barrucci  John Brucato  Thomas H. Burbine  Beth E. Clark  Ed A. Cloutis  Harold C. Connolly  Elisabetta Dotto  Joshua P. Emery  Sonia Fornasier  Cateline Lantz  Lucy F. Lim  Frederic Merlin  Alice Praet  Dennis C. Reuter  Scott A. Sandford  Amy A. Simon  Driss Takir  Dante S. Lauretta 《Meteoritics & planetary science》2020,55(4):744-765

The primary objective of the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS‐REx) mission is to return to Earth a pristine sample of carbonaceous material from the primitive asteroid (101955) Bennu. To support compositional mapping of Bennu as part of sample site selection and characterization, we tested 95 spectral indices on visible to near infrared laboratory reflectance data from minerals and carbonaceous meteorites. Our aim was to determine which indices reliably identify spectral features of interest. Most spectral indices had high positive detection rates when applied to spectra of pure, single‐component materials. The meteorite spectra have fewer and weaker absorption features and, as a result, fewer detections with the spectral indices. Indices targeting absorptions at 0.7 and 2.7–3 μm, which are attributable to hydrated minerals, were most successful for the meteorites. Based on these results, we identified a set of 17 indices that are most likely to be useful at Bennu. These indices detect olivines, pyroxenes, carbonates, water/OH‐bearing minerals, serpentines, ferric minerals, and organics. Particle size and albedo are known to affect band depth but had a negligible impact on interpretive success with spectral indices. Preliminary analysis of the disk‐integrated Bennu spectrum with these indices is consistent with expectations given the observed absorption near 3 μm. Our study prioritizes spectral indices to be used for OSIRIS‐REx spectral analysis and mapping and informs the reliability of all index‐derived data products, including a science value map for sample site selection.  相似文献   

Growth and photosynthetic responses to copper stress of an invasive cordgrass, Spartina densiflora     

Mateos-Naranjo E  Redondo-Gómez S  Cambrollé J  Enrique Figueroa M 《Marine environmental research》2008,66(4):459-465

Spartina densiflora Brongn. is found in coastal marshes of south-west Spain, growing in sediments with between 300 and 3000mg Cu kg(-1) total soil DW (450-4500mg Cu kg(-1) supposing that the soil porosity is 0.5). An experiment was designed to investigate the effect of copper from 0 to 5000mgkg(-1) (64mmoll(-1)) on the photosynthetic apparatus and the growth of S. densiflora. We also determined total ash, copper, calcium, magnesium and phosphorous concentrations, as well as C/N ratio. S. densiflora survived to concentrations as high as 320mg Cukg(-1) DW in leaves, although excess of Cu diminished water use efficiency and Ca-, Mg- and P-uptake. Also, quantum efficiency of PSII, net photosynthetic rate, stomatal conductance and pigment concentrations declined with increasing external Cu. Finally, the decline in the photosynthetic function resulted in a biomass reduction of between 50 and 80% (for 600 and 5000mg Cu kg(-1), respectively).  相似文献   

On the ecohydrology of the Yucatan Peninsula: Evapotranspiration and carbon intake dynamics across an eco‐climatic gradient          下载免费PDF全文

Jorge M. Uuh‐Sonda  Hugo A. Gutiérrez‐Jurado  Bernardo Figueroa‐Espinoza  Luis A. Méndez‐Barroso 《水文研究》2018,32(18):2806-2828

The hydrology and productivity of the ecosystems of the Yucatan Peninsula (YP) are highly constrained by two factors: (a) the lack of surface drainage networks due to the existence of a highly permeable and connected karstic aquifer roughly the size of the peninsula and (b) a climatic gradient that leads to a transition from seasonally dry deciduous and sub‐deciduous tropical forests, in the north‐western and central parts of the Peninsula, to evergreen forests, in the southern and eastern parts. As a result, surface water fluxes of the YP are restricted to evapotranspiration (ET) that are tightly coupled to ecosystems health and gross primary productivity (GPP). The magnitude and seasonal variation of these fluxes are sensitive to climatic variability and perturbations caused by extreme events such as droughts and tropical storms that are frequent in the YP. In this study, we assess the spatio‐temporal dynamics of ET and GPP above average dry and wet conditions through time series analyses of 15 years of remotely sensed data from both Moderate Resolution Imaging Spectroradiometer and Tropical Rainfall Measuring Mission satellite products. Our results show that ET and GPP follow a regional moisture and temperature gradient that highly controls the distribution of ecosystems within the peninsula. We observe that ET and GPP are in phase with the rainy season in the deciduous forests, but for the evergreen forests, only the GPP is in phase. Additionally, and with the exception of droughts on deciduous ecosystems of the northern part of the YP, the productivity of these ecosystems shows a legacy effect, responding more to a defined trajectory (wetting or drying on the previous years), rather than to punctual extreme climatic events. This has implications on the resilience of these ecosystems to natural perturbations of climate. Comparisons between deciduous and evergreen forest indicate that both types of ecosystems have different plant water use strategies in response to hydrologic variability.  相似文献   

Depth influence on biochemical performance and thallus size of the red alga Gelidium corneum          下载免费PDF全文

Endika Quintano  Isabel Díez  Nahiara Muguerza  Félix López Figueroa  José María Gorostiaga 《Marine Ecology》2018,39(1)

Recent declines in the foundation species Gelidium corneum (Hudson) J.V. Lamouroux in pristine coastal stretches of the Southeastern Bay of Biscay have been documented in which individuals showed a high bleaching incidence. Among the potential factorsthat may be responsible for these changes in G. corneum abundance, it has been suggested that high levels of irradiance may be imposing stressful environmental conditions for shallow populations. Given that light is reduced exponentially as depth increases, in this investigation we examined the influence of depth on the stress of G. corneum by comparing the performance of several biochemical parameters and thallus size in plants collected at three different depths. The results revealed that plants growing in shallow waters showed lower antioxidant activity, lower concentrations of photosynthetic pigments (Chl‐a, total carotenoids, phycoerythrin), lower internal nitrogen levels (higher C:N ratio) and shorter thallus lengths than those living in deeper waters. Some of these results may be an expression of photoacclimation, but the low antioxidant activity and total carotenoid concentration detected in plants living in shallow waters suggest that the photoprotective mechanisms of G. corneum may have failed to offset photodamage. If so, our findings support previous studies that suggest that recent changes in solar radiation are partially responsible for G. corneum declines. Nevertheless, given that the metabolic performance of macroalgae is determined by the inter‐play of irradiance with other factors, including temperature and nutrient availability, further research is needed to reach a better understanding of the factors causing stress in G. corneum.  相似文献   

Mineralogy,petrology, and oxygen isotopic compositions of chondritic and achondritic lithologies in the anomalous CB carbonaceous chondrites Sierra Gorda 013 and Fountain Hills     

Alexander N. Krot  Kazuhide Nagashima  Marina A. Ivanova  Dante Lauretta  Guy Libourel  Brandon C. Johnson  Frank E. Brenker  Viktoria Hoffman  Martin Bizzarro 《Meteoritics & planetary science》2024,59(4):754-777

The CB (Bencubbin-like) metal-rich carbonaceous chondrites are subdivided into the CB_a and CB_b subgroups. The CB_a chondrites are composed predominantly of ~cm-sized skeletal olivine chondrules and unzoned Fe,Ni-metal ± troilite nodules. The CB_b chondrites are finer grained than the CB_as and consist of chemically zoned and unzoned Fe,Ni-metal grains, Fe,Ni-metal ± troilite nodules, cryptocrystalline and skeletal olivine chondrules, and rare refractory inclusions. Both subgroups contain exceptionally rare porphyritic chondrules and no interchondrule fine-grained matrix, and are interpreted as the products of a gas–melt impact plume formed by a high-velocity collision between differentiated planetesimals about 4562 Ma. The anomalous metal-rich carbonaceous chondrites, Fountain Hills and Sierra Gorda 013 (SG 013), have bulk oxygen isotopic compositions similar to those of other CBs but contain coarse-grained igneous clasts/porphyritic chondrule-like objects composed of olivine, low-Ca-pyroxene, and minor plagioclase and high-Ca pyroxene as well as barred olivine and skeletal olivine chondrules. Cryptocrystalline chondrules, zoned Fe,Ni-metal grains, and interchondrule fine-grained matrix are absent. In SG 013, Fe,Ni-metal (~80 vol%) occurs as several mm-sized nodules; magnesiochromite (Mg-chromite) is accessory; daubréelite and schreibersite are minor; troilite is absent. In Fountain Hills, Fe,Ni-metal (~25 vol%) is dispersed between chondrules and silicate clasts; chromite and sulfides are absent. In addition to a dominant chondritic lithology, SG 013 contains a chondrule-free lithology composed of Fe,Ni-metal nodules (~25 vol%), coarse-grained olivine and low-Ca pyroxene, interstitial high-Ca pyroxene and anorthitic plagioclase, and Mg-chromite. Here, we report on oxygen isotopic compositions of olivine, low-Ca pyroxene, and ±Mg-chromite in Fountain Hills and both lithologies of SG 013 measured in situ using an ion microprobe. Oxygen isotope compositions of olivine, low-Ca pyroxene, and Mg-chromite in these meteorites are similar to those of magnesian non-porphyritic chondrules in CB_a and CB_b chondrites: on a three-isotope oxygen diagram (δ¹⁷O vs. δ¹⁸O), they plot close to a slope-1 (primitive chondrule mineral) line and have a very narrow range of Δ¹⁷O (=δ¹⁷O–0.52 × δ¹⁸O) values, −2.5 ± 0.9‰ (avr ± 2SD). No isotopically distinct relict grains have been identified in porphyritic chondrule-like objects. We suggest that magnesian non-porphyritic (barred olivine, skeletal olivine, cryptocrystalline) chondrules in the CB_as, CB_bs, and porphyritic chondrule-like objects in SG 013 and Fountain Hills formed in different zones of the CB impact plume characterized by variable pressure, temperature, cooling rates, and redox conditions. The achondritic lithology in SG 013 represents fragments of one of the colliding bodies and therefore one of the CB chondrule precursors. Fountain Hills was subsequently modified by impact melting; Fe,Ni-metal and sulfides were partially lost during this process.  相似文献   

Developing Data-Rich Video of Surface Water–Groundwater Interactions for Public Engagement     

Catherine Christenson  David J. Hart  Michael Cardiff  Susan Richmond  Dante Fratta 《Ground water》2022,60(3):426-433

Communication of hydrologic data to the public can be improved by connecting data to the places they represent. In our example of data communication, we coupled hydrologic data with simultaneously collected video as both a scientific and public engagement tool. This note presents a method for collecting spatially and temporally dense datasets of water-quality and geophysical data on small streams and lakes, and for displaying the data in a user-friendly format using commercially available software. With this method, multiple instruments are mounted on a canoe and a controlled survey float is carried out to collect data. The data stream is georeferenced and logged using an Arduino microcontroller to provide detailed information about spatial variability. We employed these continuous data-collection methods at small streams and lakes across Wisconsin, USA. Comparison of stream-float sensor data to lab reported data, data collected by alternative sensors, and previously collected data in our study areas indicates that the low-cost temperature, electrical conductivity, pH, and dissolved oxygen sensors performed well. GoPro cameras recorded video throughout the duration of data collection. Our established water-quality and geophysical data collection methods are inexpensive, fast, and reliable, which qualify them as excellent tools for fine-scale spatial understanding of stream and lake habitats' health. Data-rich video connects point measurements of water properties to the appearance of the native environment. This method helps improve our understanding of groundwater and surface water interactions in complex hydrogeologic systems, enhance communication amongst stakeholders, and provide context when monitoring and managing sensitive habitats.  相似文献   

The formation and alteration of the Renazzo‐like carbonaceous chondrites III: Toward understanding the genesis of ferromagnesian chondrules          下载免费PDF全文

Devin L. Schrader  Harold C. Connolly Jr.  Dante S. Lauretta  Thomas J. Zega  Jemma Davidson  Kenneth J. Domanik 《Meteoritics & planetary science》2015,50(1):15-50

To better understand the formation conditions of ferromagnesian chondrules from the Renazzo‐like carbonaceous (CR) chondrites, a systematic study of 210 chondrules from 15 CR chondrites was conducted. The texture and composition of silicate and opaque minerals from each observed FeO‐rich (type II) chondrule, and a representative number of FeO‐poor (type I) chondrules, were studied to build a substantial and self‐consistent data set. The average abundances and standard deviations of Cr₂O₃ in FeO‐rich olivine phenocrysts are consistent with previous work that the CR chondrites are among the least thermally altered samples from the early solar system. Type II chondrules from the CR chondrites formed under highly variable conditions (e.g., precursor composition, redox conditions, cooling rate), with each chondrule recording a distinct igneous history. The opaque minerals within type II chondrules are consistent with formation during chondrule melting and cooling, starting as S‐ and Ni‐rich liquids at 988–1350 °C, then cooling to form monosulfide solid solution (mss) that crystallized around olivine/pyroxene phenocrysts. During cooling, Fe,Ni‐metal crystallized from the S‐ and Ni‐rich liquid, and upon further cooling mss decomposed into pentlandite and pyrrhotite, with pentlandite exsolving from mss at 400–600 °C. The composition, texture, and inferred formation temperature of pentlandite within chondrules studied here is inconsistent with formation via aqueous alteration. However, some opaque minerals (Fe,Ni‐metal versus magnetite and panethite) present in type II chondrules are a proxy for the degree of whole‐rock aqueous alteration. The texture and composition of sulfide‐bearing opaque minerals in Graves Nunataks 06100 and Grosvenor Mountains 03116 suggest that they are the most thermally altered CR chondrites.  相似文献   

Experimental and theoretical simulations of ice sublimation with implications for the chemical,isotopic, and physical evolution of icy objects     

Robert H. Brown  Dante S. Lauretta  Britney Schmidt  John Moores 《Planetary and Space Science》2012,60(1):166-180

Recent ground-based and spacecraft observations of comets in the inner solar system reveal two distinct features that provide important insight into their origin and evolution. The first of these is the observation that the D/H ratio of water vapor in cometary comae is significantly higher than that in Vienna Standard Mean Ocean Water (VSMOW). The second observation is that cometary jets are bursty (i.e, roughly steady state emissions that are punctuated with short-lived outbursts of water vapor and other materials) (Hughes, 1990, Soderblom et al., 2002, Soderblom et al., 2004a, Soderblom et al., 2004b). We present an experimental and theoretical study of ice sublimation in a vacuum that reveals several heretofore unknown and fundamental characteristics about the kinetics and mechanisms of ice sublimation that may explain both of these observed phenomena. In particular, we observe quasi-periodic sublimation cascades on time scales of hours to days, the D/H ratio in the vapor issuing from the sample is in general different from that of the sample, and in many cases, quasi-periodic changes in the D/H ratio of the vapor accompany the sublimation cascades. Changes are also observed in the infrared spectrum of the sample before, during and after a cascade that are consistent with our hypothesis that vacuum sublimation of water ice is a diffusive process that works to leave behind the most strongly bound molecules. Finally, we speculate as to whether the effects observed in the lab can be extrapolated to cometary-nucleus-scale phenomena.  相似文献