chlorophyll Articles
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Corals as light collectors: an integrating sphere approach
An integrating sphere was used to estimate the fraction of the incident quantum flux absorbed by a coral colony placed within it. This method allows one to examine the in vivo light absorption of intact coral colonies. We used this method to study effects of colony morphology, size, and photoacclimation status on the light harvesting efficiency by the zooxanthellae. Light absorption per unit of ...
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Use of PCA-RBF model for prediction of chlorophyll-a in Yuqiao Reservoir in the Haihe River Basin, China
Chlorophyll-a is a well-accepted index for phytoplankton abundance and population of primary producers in an aquatic environment. The relationships between chlorophyll-a and 18 chemical, physical and biological water quality variables in YuQiao Reservoir (YQR) in the Haihe River Basin in P.R. China were studied by using principal component analysis (PCA) coupled with a radial basis function ...
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Growth inhibition of
Microcystis aeruginosa by white-rot fungusLopharia spadicea Harmful cyanobacterial blooms cause water deterioration and threaten human health. It is necessary to remove harmful cyanobacteria with useful methods. A bio-treatment may be one of the best ways to do this. A strain of specific white-rot fungus, Lopharia spadicea, with algicidal ability was isolated. Its algicidal ability on algae under various conditions was determined using three main ...
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Pigment-based identification of ozone-damaged pine needles as a basis for spectral segregation of needle conditions
Received for publication June 6, 2008. Air pollution affects large areas of forest, and field assessment of these effects is a costly, site-specific process. This paper establishes a biochemical basis for identifying ozone-damaged pine trees to facilitate efficient remote sensing assessment of air pollution damage. Several thousand live needles were collected from ponderosa pine (Pinus ponderosa) ...
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Luxury production of leaf chlorophyll and mid-season recovery from nitrogen deficiencies in corn
Deficiencies of N during the growth of corn (Zea mays L.) are often diagnosed by using chlorophyll meters that measure chlorophyll content in leaves. The diagnoses are based on the assumption that above-optimal supplies of N do not significantly influence chlorophyll meter readings (CMRs). The objective of this research was to assess the possibility that above-optimal supplies of N impacted ...
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Application of Bayesian regularized BP neural network model for analysis of aquatic ecological data - A case study of chlorophyll-a prediction in Nanzui water area of Dongting Lake
Bayesian regularized BP neural network (BRBPNN) technique was applied in the chlorophyll-a prediction of Nanzui water area in Dongting Lake. Through BP network interpolation method, the input and output samples of the network were obtained. After the selection of input variables using stepwise/multiple linear regression method in SPSS 11.0 software, the BRBPNN model was established between ...
By IOS Press
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Sedimentation of chlorophylls in an Arctic fjord under freshwater discharge
Sedimentation of chlorophylls was studied during summer 1997 in Adventfjorden (Spitsbergen, Arctic). During the period of study, the water column was found to be well stratified by a freshened surface layer (salinity <31 PSS). A high load of suspended particulate matter from riverine discharge reduced the euphotic zone to an interval of 0.4–1.1m. Total particulate matter sedimentation rates were ...
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Modeling impacts of water transfers on alleviation of phytoplankton aggregation in Lake Taihu
A water transfer project has been ongoing since 2002 to alleviate severe phytoplankton aggregation in Lake Taihu. This study aimed to quantify the effectiveness of the water transfer project on alleviation of phytoplankton aggregation in Lake Taihu on a short-term scale. In this study, a spatially distributed hydrodynamic-phytoplankton model was used to predict the short-term (3–4 days) ...
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Content of magnesium in Ginkgo biloba leaves
The aim of this study was to investigate the content of magnesium in Ginkgo biloba leaves and compared with those Urtica dioica. The magnesium was determined by atomic absorption spectrophotometry: Ginkgo biloba leaves contained (456 ?g/g) of Mg and Urtica dioica leaves 396 ?g/g. The concentration of magnesium in the aqueous extracts prepared from Ginkgo biloba leaves was about two-fold higher ...
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Determination of Chlorophyll Content in Rapeseed by Spectrophotometry
Rapeseed is an important oil crop in my country, and rapeseed oil is one of the important edible oils in China. The chlorophyll content in rapeseed oil directly affects the oil processing cost and the shelf life of the oil. This article refers to "GB/T 22182-2008/ISO 10519:1997 Rapeseed Chlorophyll Content Determination Spectrophotometer Method" and "NY/T 1287-2007 Rapeseed Chlorophyll Content ...
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Coastal water quality in the Kihei and Lahaina districts of the island of Maui, Hawaiian Islands. Impacts from physical habitat and groundwater seepage: implications for water quality standards
Water quality in terms of nutrient concentrations, turbidity, suspended solids, and chlorophyll a, was studied during 2000–2001 at a total of 27 beaches in the Kihei and West Maui–Lahaina districts of Maui, Hawaiian Islands. Nitrate concentrations varied widely and averaged as much as 15–20 µM at some beaches. Most turbidities fell in the range 1–10 nephelometric turbidity units. Resuspension of ...
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Particulate matter effect on biometric and biochemical attributes of fruiting plants
Dust accumulation capacity of Ficus carica L. and Psidium guajava L. was investigated from eight different sites of Multan, Pakistan. Leaves of both plants were used for analyzing biometric (leaf area, fresh and dry weights) and biochemical attributes (chlorophyll contents, carotenoids and ascorbic acid). Maximum dust accumulation was occurred in the plants growing near road sites, while, ...
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Physiological analysis of silver nanoparticles and AgNO3 toxicity to Spirodela polyrhiza
Silver nanoparticles (AgNPs) are commonly used in consumer products for their antibacterial activity. Silver nanoparticles may adversely influence organisms when released into the environment. The present study investigated the effect of AgNPs on the growth, morphology, and physiology of the aquatic plant duckweed (Spirodela polyrhiza). The toxicity of AgNPs and AgNO3 was also compared. The ...
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A comparison of two techniques for nondestructive measurement of chlorophyll content in grapevine leaves
Traditional methods for chlorophyll (Chl) measurement include wet chemical extractions and handheld Chl meters. The recent availability of small and affordable radiometers has provided means to estimate Chl from reflectance measurements. This paper compares the performance of a handheld SPAD Chl meter and a recently developed Red Edge Chlorophyll Index (CIred edge) for Chl estimation in grapevine ...
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Monitoring of phytoplankton biomass and nutrients in a polluted stream
The spatial and temporal variations in the concentrations of nutrients (NH4+, NO2−, PO43−, SiO4−) and chlorophyll a were monitored simultaneously in a slow-flowing watercourse (Saricay Stream, Turkey), which runs in a ruralurban gradient. Chlorophyll a concentrations ranged between 0.044 g l-1 and 206.15 g l-1 and, in general, the higher concentrations of chlorophyll a and ammonium were measured ...
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Resuspension-mediated temporal variation in Phosphorus concentrations and internal loading
Received for publication February 11, 2008. Sediment resuspension is an important factor for nutrient cycling in shallow lakes. Temporal variation in sediment resuspension and its influence on P concentrations and internal loading were studied in the shallow and eutrophic Kirkkojärvi basin. Gross sedimentation and sediment resuspension were estimated with sediment traps during three exposure ...
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CO2 photoassimilation, chlorophyll fluorescence, lipid peroxidation and yield in cotton (Gossypium hirsutum L. cv Giza 65) in response to O3
Over the recent years, convincing evidence has emerged of both a decrease in stratospheric ozone (O3) and an increase in tropospheric O3 concentration. There is an intimate relationship between O3 and photosynthesis (A), which is ultimately linked to plant growth and yield. Photosynthetic response, chlorophyll fluorescence, Rubisco activity, lipid peroxidation and yield of an Egyptian cultivar of ...
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Effects of maturity on chlorophyll-related absorption in nectarines, measured by non-destructive time-resolved reflectance spectroscopy
The ripening of fruits like nectarines and peaches is characterised by the decrease in chlorophyll content or colour of the fruit flesh. However, measuring the colour of fruit flesh is usually not conducted, as there is a lack of suitable techniques. Time-Resolved Reflectance Spectroscopy (TRS) is a novel technique that can measure the light absorbed by the fruit flesh. Using a laser light beam ...
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Availability of different phosphorus forms in agricultural soil to
Microcystis aeruginosa We investigated the availability of different forms of particulate soil phosphorus (P) to Microcystis aeruginosa by sequential extraction and bioassay. We cultured M. aeruginosa in media containing, as the sole source of P, soils sequentially extracted with 1 M NH4Cl, 0.11 M bicarbonate dithionite, 1 M NaOH, and 0.5 M HCl. Analyses of chlorophyll-a, particulate organic carbon, and particulate ...
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Operation and recovery of a seasonally-loaded UK waste stabilisation pond system
An intermittent discharge waste stabilisation pond system was trialled for treatment of a seasonal wastewater load from a campsite. The system showed rapid acclimatisation to incoming load, with chlorophyll-a exceeding 700 mg l−1 within 2 weeks and filtered and unfiltered effluent biochemical oxygen demand below 20 and 30 mg l−1 respectively. Good performance continued for some ...
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