The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
A B Bottcher - One of the best experts on this subject based on the ideXlab platform.
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sugarcane production impact on nitrogen and phosphorus in drainage Water from an everglades histosol
Journal of Environmental Quality, 1994Co-Authors: F J Coale, Forrest T Izuno, A B BottcherAbstract:The Everglades Agricultural Area (EAA) in southern Florida is a 280 000-ha tract of land that has come under scrutiny by environmental, agricultural industry, and government Water management groups that are concerned with the impact of nutrient-enriched drainage Water on the ecology of adjoining Bodies of Water and wetlands. Sugarcane (Saccharum sp.) is grown on 155 000 ha or 78% of the cultivated organic soils in the EAA. The objectives of this study were to determine the N and P concentrations and off-field loads in drainage Water from sugarcane and fallow fields. Sugarcane was planted in four of eight hydraulically independent and similar field plots. Four plots were maintained fallow (.)
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phosphorus in drainage Water from sugarcane in the everglades agricultural area as affected by drainage rate
Journal of Environmental Quality, 1994Co-Authors: F J Coale, Forrest T Izuno, A B BottcherAbstract:Sugarcane (interspecific hybrids of Saccharum spp.) is grown on 78% (156,000 ha) of the cultivated organic soils of the Everglades Agricultural Area (EAA) of southern Florida. Recently, the EAA has come under scrutiny because of concerns with the impact of nutrient-rich drainage Water from organic soils on the ecology of adjoining Bodies of Water and wetlands. The objectives of our research were to determine the effects of field drainage rate on P concentration and off-field P loads in drainage Water from sugarcane grown on organic soils of the EAA and to determine the effect of field drainage rate on sugarcane productivity and sugar yield (.)
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nutrient accumulation and removal by sugarcane grown on everglades histosols
Agronomy Journal, 1993Co-Authors: F J Coale, C A Sanchez, Forrest T Izuno, A B BottcherAbstract:Sugarcane (interspecific hybrids of Saccharum spp.) is Florida's most valuable agronomic crop. Recently, sugarcane production has come under scrutiny because of concerns regarding the impact of nutrient-rich drainage Water on the ecology of adjoining Bodies of Water and wetlands. The objective of our research was to define the N, P, K, Ca, and Mg seasonal accumulation patterns in the aerial portion of sugarcane grown on organic soils of the Everglades Agricultural Area. Sugarcane fields were sampled on 30 to 60 d intervals during the plant-cane and first-ratoon crops. Dry weight, N, P, K, Ca, and Mg accumulation were determined and characterized by logistic growth models. Dry weight accumulation averaged 0.15 t ha −1 d −1 during the grand growth period [...]
J W Head - One of the best experts on this subject based on the ideXlab platform.
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fate of outflow channel effluents in the northern lowlands of mars the vastitas borealis formation as a sublimation residue from frozen ponded Bodies of Water
Journal of Geophysical Research, 2002Co-Authors: M A Kreslavsky, J W HeadAbstract:[1] We analyze the fate of the Hesperian-aged outflow channel effluents emplaced into the northern lowlands of Mars. We have modeled the evolution of these effluents under the assumption that they were emplaced under a range of atmospheric conditions comparable to those of today and thought to have prevailed in the Hesperian. Under these conditions we find that the evolution of the sediment-loaded Water after it left the channels includes three phases. Phase 1: Emplacement and intensive cooling: Violent emplacement of Water followed by a short period of intensive evaporation from the surface and near-surface layer, and intensive convection. During this phase the Water maintained and redistributed its large suspended sediment load. Water vapor strongly influenced the climate, at least for a geologically short time. When the temperature of the Water reached the temperature of the maximum density or the freezing point, boiling and intensive convection ceased and the Water deposited the sediments. Phase 2: Freezing solid: Geologically rapid freezing of the Water body accompanied by weak convective Water movement occurred over a period of the order of ∼104 years. Phase 3: Sublimation and loss: This period involved sublimation of the ice and lasted longer than the freezing phase. The rate and latitudinal dependence of the sublimation, as well as the location of Water vapor condensation, crucially depend on the planetary obliquity, climate, and sedimentary veneering of the ice. Phase 3 would have been very short geologically (∼105–106 years) if an insulating sedimentary layer did not build up rapidly. If such an insulating layer did form rapidly, sublimation could cease and residual ice hundreds of meters thick could remain below the surface today. The northern lowlands of Mars are largely covered by the Late Hesperian-aged Vastitas Borealis Formation (VBF), which has sharp boundaries clearly seen in the map of kilometer-scale roughness, and a distinctive kilometer-scale roughness signature. We examine detrended topography data and find evidence that the VBF is underlain at very shallow depths by an Early Hesperian ridged volcanic plains substrate, rather than frozen Water deposits remaining from the outflow channel events. Analysis of the VBF roughness characteristics suggests at least 100 m thickness of sediments on top of the underlying volcanic ridged plains. The total inferred volume of the VBF material approximately corresponds to the volume of material removed from the outflow channels. These results support a model in which the Vastitas Borealis Formation predominantly represents the sedimentary residue remaining after the sediment-laden Water effluents of the outflow channels ponded in the northern lowlands and rapidly froze solid and sublimed. The distinctive facies of the VBF are interpreted to be related to the freezing, sublimation, and residue of the outflow channel effluents. Ridged facies are dominantly marginal and are interpreted to be related to ice sheet lateral retreat. Knobby facies occur throughout and are interpreted to be due to a variety of causes, including deWatering, de-icing and brine-related processes, and kame-like ice residues. Grooved facies are interpreted to represent postsublimation uplift and fracturing due to load removal. The mottled facies may represent bright ejecta whose albedo is related to buried sedimentary or evaporitic residues. Presently, the most likely sites to find frozen remnants of the Hesperian ocean are below the floors of stealth craters underlying the VBF. On the basis of these findings and interpretations, we make predictions for the fate of the outflow channel Water vapor and the nature of the Martian hydrologic cycle during the Hesperian. If Noachian-aged oceans existed, conditions at that time would be similar to those described for a Hesperian ocean as soon as a global cryosphere was formed. If any residual deposits remain in the northern lowlands from a proposed Noachian ocean, they would lie below both the VBF and the underlying sequence of Hesperian ridged plains.
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chryse planitia mars topographic configuration outflow channel continuity and sequence and tests for hypothesized ancient Bodies of Water using mars orbiter laser altimeter mola data
Journal of Geophysical Research, 2001Co-Authors: M A Ivanov, J W HeadAbstract:Many of the largest and most prominent outflow channels on Mars debouch into Chryse Planitia. Pre-Mars Global Surveyor topographic data show Chryse to be a closed depression almost 2000 km in diameter. New Mars Orbiter Laser Altimeter (MOLA) data reveal the following: (1) Chryse is not a locally closed basin but instead opens into the North Polar basin. (2) The highly distinctive morphology of the six largest predominantly Hesperian-aged channels (Kasei, Maja, Simud, Tiu, Ares, and Mawrth) disappears into the northern lowlands at average elevations that all occur within less than ∼170 m of a mean elevation of −3742 (SD = 153 m), over a lateral distance in excess of 2500 km. (3) The elevations where the distinctive morphology of each channel disappears all fall within ∼190 m of Contact 2, a boundary mapped by Parker et al. [1993] and interpreted to represent an ancient shoreline, and the mean elevation values of Contact 2 and circum-Chryse channel termini fall within 18 m of each other. In contrast, the termini of seven later Amazonian-aged channels emerging from Elysium into Utopia Planitia are spread over a vertical range of >1500 m. (4) Topographic evidence of the continuation of some of the outflow channels can be observed for distances of 250–450 km into the North Polar basin, but the morphology is subdued and distinctly different. (5) The nature of this less distinctive topography and its crosscutting relationships show that Simud and Tiu are likely to represent the youngest activity (specifically crosscutting Ares Valles). (6) The distinctive change in channel morphology is consistent with rapid loss of energy encountered at base level (subaerial/submarine boundary) and emplacement into a shallow submarine environment. Channel characteristics, lack of distinctive deltas or lobes, and continuation of subdued channel morphology suggest hyperpychnal flow and the possibility of density/turbidity currents. Estimates of the volumes of individual channel events are wide-ranging. The minimum volume estimates of Carr [1996] suggest that 46 such events would be required to fill the basin to the level of Contact 2 and thus that the channels may have emptied into an existing standing body of Water. Volume estimates of Baker et al. [1991] assume that single individual events may have filled the basin to the level of Contact 2, thus requiring significant Water loss between events and refilling during subsequent events to essentially the same level. In both end-member cases these observations are consistent with the presence of large standing Bodies of Water in the northern lowlands in Hesperian-Early Amazonian times.
F J Coale - One of the best experts on this subject based on the ideXlab platform.
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sugarcane production impact on nitrogen and phosphorus in drainage Water from an everglades histosol
Journal of Environmental Quality, 1994Co-Authors: F J Coale, Forrest T Izuno, A B BottcherAbstract:The Everglades Agricultural Area (EAA) in southern Florida is a 280 000-ha tract of land that has come under scrutiny by environmental, agricultural industry, and government Water management groups that are concerned with the impact of nutrient-enriched drainage Water on the ecology of adjoining Bodies of Water and wetlands. Sugarcane (Saccharum sp.) is grown on 155 000 ha or 78% of the cultivated organic soils in the EAA. The objectives of this study were to determine the N and P concentrations and off-field loads in drainage Water from sugarcane and fallow fields. Sugarcane was planted in four of eight hydraulically independent and similar field plots. Four plots were maintained fallow (.)
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phosphorus in drainage Water from sugarcane in the everglades agricultural area as affected by drainage rate
Journal of Environmental Quality, 1994Co-Authors: F J Coale, Forrest T Izuno, A B BottcherAbstract:Sugarcane (interspecific hybrids of Saccharum spp.) is grown on 78% (156,000 ha) of the cultivated organic soils of the Everglades Agricultural Area (EAA) of southern Florida. Recently, the EAA has come under scrutiny because of concerns with the impact of nutrient-rich drainage Water from organic soils on the ecology of adjoining Bodies of Water and wetlands. The objectives of our research were to determine the effects of field drainage rate on P concentration and off-field P loads in drainage Water from sugarcane grown on organic soils of the EAA and to determine the effect of field drainage rate on sugarcane productivity and sugar yield (.)
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nutrient accumulation and removal by sugarcane grown on everglades histosols
Agronomy Journal, 1993Co-Authors: F J Coale, C A Sanchez, Forrest T Izuno, A B BottcherAbstract:Sugarcane (interspecific hybrids of Saccharum spp.) is Florida's most valuable agronomic crop. Recently, sugarcane production has come under scrutiny because of concerns regarding the impact of nutrient-rich drainage Water on the ecology of adjoining Bodies of Water and wetlands. The objective of our research was to define the N, P, K, Ca, and Mg seasonal accumulation patterns in the aerial portion of sugarcane grown on organic soils of the Everglades Agricultural Area. Sugarcane fields were sampled on 30 to 60 d intervals during the plant-cane and first-ratoon crops. Dry weight, N, P, K, Ca, and Mg accumulation were determined and characterized by logistic growth models. Dry weight accumulation averaged 0.15 t ha −1 d −1 during the grand growth period [...]
Austin Troy - One of the best experts on this subject based on the ideXlab platform.
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mapping the concentrations of total suspended matter in lake taihu china using landsat 5 tm data
International Journal of Remote Sensing, 2006Co-Authors: Weiqi Zhou, Shixin Wang, Yadong Zhou, Austin TroyAbstract:Remote sensing techniques can be used to estimate and map the concentrations of suspended matter in inland Water, providing both spatial and temporal information. Although an empirical approach to remote sensing of inland Waters has been carried out frequently, satellite imagery has not been incorporated into routine lake monitoring programmes due in part to the lack of a standard prediction equation with multi‐temporal capacity for suspended matter. Empirical and physical models must be developed for each lake and its corresponding turbidity composition if they are to be compared over time, or with other Bodies of Water. This study aimed to develop and apply multi‐temporal models to estimate and map the concentrations of total suspended matter (TSM) in Lake Taihu, China. Two Landsat‐5 Thematic Mapper (TM) images and nearly contemporaneous in situ measurements of TSM were used. A modified Dark‐Object Subtraction (DOS) method was used, and appeared to be adequate for atmospheric correction. The relationshi...
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mapping the concentrations of total suspended matter in lake taihu china using landsat 5 tm data
International Journal of Remote Sensing, 2006Co-Authors: Weiqi Zhou, Shixin Wang, Yi Zhou, Austin TroyAbstract:Remote sensing techniques can be used to estimate and map the concentrations of suspended matter in inland Water, providing both spatial and temporal information. Although an empirical approach to remote sensing of inland Waters has been carried out frequently, satellite imagery has not been incorporated into routine lake monitoring programmes due in part to the lack of a standard prediction equation with multi‐temporal capacity for suspended matter. Empirical and physical models must be developed for each lake and its corresponding turbidity composition if they are to be compared over time, or with other Bodies of Water. This study aimed to develop and apply multi‐temporal models to estimate and map the concentrations of total suspended matter (TSM) in Lake Taihu, China. Two Landsat‐5 Thematic Mapper (TM) images and nearly contemporaneous in situ measurements of TSM were used. A modified Dark‐Object Subtraction (DOS) method was used, and appeared to be adequate for atmospheric correction. The relationshi...
Yi Zhou - One of the best experts on this subject based on the ideXlab platform.
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anti oxidative feedback and biomarkers in the intertidal seagrass zostera japonica induced by exposure to copper lead and cadmium
Marine Pollution Bulletin, 2016Co-Authors: Haiying Lin, Tao Sun, Yi Zhou, Xiaomei ZhangAbstract:To investigate the potential influences of anthropogenic pollutants, we evaluated the responses of the intertidal seagrass Zostera japonica to three heavy metals: copper (Cu), lead (Pb), and cadmium (Cd). Z. japonica was exposed to various concentrations of Cu, Pb, and Cd (0, 0.5, 5, 50μM) over seven days. The effects were then analyzed using the antioxidant enzyme catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione peroxidase (GPX), and lipid peroxidation measured using malondialdehyde (MDA) as proxy. Metal accumulation in the above-ground tissues and phenotypic changes were also investigated. Our results revealed that heavy metal concentration increased in seagrass exposed to high levels of metals. Z. japonica has great potential for metal accumulation and a suitable candidate for the decontamination of moderately Cu contaminated Bodies of Water and can also potentially enhanced efforts of environmental decontamination, either through phytoextraction abilities or by functioning as an indicator for monitoring programs that use SOD, CAT, GPX, POD and MDA as biomarkers.
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mapping the concentrations of total suspended matter in lake taihu china using landsat 5 tm data
International Journal of Remote Sensing, 2006Co-Authors: Weiqi Zhou, Shixin Wang, Yi Zhou, Austin TroyAbstract:Remote sensing techniques can be used to estimate and map the concentrations of suspended matter in inland Water, providing both spatial and temporal information. Although an empirical approach to remote sensing of inland Waters has been carried out frequently, satellite imagery has not been incorporated into routine lake monitoring programmes due in part to the lack of a standard prediction equation with multi‐temporal capacity for suspended matter. Empirical and physical models must be developed for each lake and its corresponding turbidity composition if they are to be compared over time, or with other Bodies of Water. This study aimed to develop and apply multi‐temporal models to estimate and map the concentrations of total suspended matter (TSM) in Lake Taihu, China. Two Landsat‐5 Thematic Mapper (TM) images and nearly contemporaneous in situ measurements of TSM were used. A modified Dark‐Object Subtraction (DOS) method was used, and appeared to be adequate for atmospheric correction. The relationshi...