Optical properties, Nutrients and Phytoplankton of freshwater Coastal Dune Lakes in South-east Queensland

1988 ◽  
Vol 39 (6) ◽  
pp. 805 ◽  
Author(s):  
LC Bowling
Keyword(s):  
Optical Properties ◽  
Chlorophyll A ◽  
Coastal Dune ◽  
Photosynthetically Available Radiation ◽  
Attenuation Coefficients ◽  
Low Concentrations ◽  
Dune Lakes ◽  
Lake Waters

Gilvin was the main attenuator of photosynthetically available radiation (PAR) in 26 freshwater coastal dune lakes, despite most being only slightly humic (range 0.000-27.866 m-1, median = 1.088 m-1). Most were also non-turbid [range 0.27-3.00 nephelometric turbidity units (NTU), median = 0.77 NTU] and had low concentrations of chlorophyll a (range 0.212-15.869 �g I-1, median = 3.285 �g I-1). Accordingly there was only slight to moderate attenuation of PAR in most lakes, the majority having mean downwelling vertical attenuation coefficients of less than 1.0 m-1. However, Secchi depths indicate that the lake waters were more transparent during this study than previously reported in the literature. The lakes were typically oligotrophic, acidic, and of low conductivity. Desmids and Peridinium spp. dominated the phytoplankton, although Dynobryon cylindricum Imhof. and various Chlorococcales were also common.

scholarly journals Dependence of spectral distribution of inherent optical properties of lake waters on the concentrations of different water constituents

2007 ◽  
Vol 38 (3) ◽  
pp. 265-285 ◽  
Author(s):  
Birgot Paavel ◽  
Helgi Arst ◽  
Antti Herlevi
Keyword(s):  
Organic Matter ◽  
Optical Properties ◽  
Dissolved Organic Matter ◽  
Optically Active ◽  
Total Absorption ◽  
Attenuation Coefficients ◽  
Inherent Optical Properties ◽  
Lake Waters ◽  
Active Substances ◽  
Optically Active Substances

The study focuses on the analysis of inherent optical properties of lake waters characterized by consisting of several optically active substances (OAS) (phytoplankton, suspended particles and dissolved organic matter). The results obtained can be useful for deriving the algorithms of optical remote sensing models which need the spectral data on inherent optical properties of the aquatic environment. The spectral absorption and attenuation coefficients were measured in situ using the instrument ac-9 for eight wavelengths in the range of 400–700 nm. The investigation sites were five Finnish and six Estonian lakes. The concentrations of chlorophyll a and total suspended particulate matter, as well as the absorption coefficient of coloured dissolved organic matter (at 380 nm) were determined in a laboratory from water samples taken concurrently with ac-9 measurements. There are three main objectives: (1) to calculate the values of absorption and specific absorption coefficients of tripton on the basis of ac-9 and laboratory data; (2) to estimate the contribution of pure water, chlorophyll a, dissolved organic matter and tripton to the total absorption and attenuation coefficients (results for ac-9 wavelengths and also for the PAR region, 400–700 nm); and (3) to determine the slope (and its variability) of the scattering coefficient spectrum for each measurement series and to estimate the reasons of this variability. At the wavelength of 532 nm the values of the specific absorption coefficient of tripton varied between 0.013 and 0.098 L mg−1 m−1, while the slope of its spectrum ranged from 0.0060 to 0.0109 nm−1. The contributions of different components of the aquatic medium to the total absorption/attenuation coefficients varied noticeably from lake to lake. The slope of the scattering coefficient spectrum was in the range of 0.32–2.5, the multiple regression between the slope and three main optically active substances jointly gave the determination coefficient R2(adjusted)=0.655.

scholarly journals An extended PROSPECT: Advance in the leaf optical properties model separating total chlorophylls into chlorophyll a and b

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yao Zhang ◽  
Jingfeng Huang ◽  
Fumin Wang ◽  
George Alan Blackburn ◽  
Hankui K. Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chlorophyll A ◽  
Leaf Optical Properties ◽  
Chlorophyll A And B

Correlation between Chlorophyll-a Concentration and Environmental Factors in Jihongtan Reservoir

2011 ◽  
Vol 356-360 ◽  
pp. 959-962
Author(s):  
Ji Ping Ma ◽  
Cui Jie Rui ◽  
Jian Hua Ge ◽  
Yu Hua Liu ◽  
Zhi Wen Song ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Statistical Method ◽  
Chlorophyll A ◽  
Potassium Permanganate ◽  
Total Nitrogen ◽  
Average Concentration ◽  
Low Concentrations ◽  
High Concentrations

Based on the Jihogntan reservoir’s monitoring data from 2006 to 2009, eutrophication of Jihongtan reservoir was assessed. The result showed that the nutrition level of the Jihongtan reservoir was middle in recent years. The average concentration of chlorophyll-a(Chla) was higher in summer and autumn than in spring and winter. The correlation between concentration of Chla and some environmental factors was studied by statistical method, and seasonal variation of Chla and the extent of eutrophication were also analyzed. The results showed that the correlations between Chla and total nitrogen(TN), dissolved oxygen(DO) and transparency were significantly negative, and that between Chla and total phosphorus(TP), temperature(T) and potassium permanganate index(COD Mn) were significantly positive. The growth of phytoplankton was promoted by TP and TN at low concentrations, and inhibited by TN at high concentrations.

scholarly journals Evaluation of Ocean Color Remote Sensing Algorithms for Diffuse Attenuation Coefficients and Optical Depths with Data Collected on BGC-Argo Floats

2020 ◽  
Vol 12 (15) ◽  
pp. 2367
Author(s):  
Xiaogang Xing ◽  
Emmanuel Boss ◽  
Jie Zhang ◽  
Fei Chai
Keyword(s):  
Sea Surface ◽  
Homogeneous Distribution ◽  
Photosynthetically Available Radiation ◽  
Layer Depth ◽  
Attenuation Coefficients ◽  
Argo Floats ◽  
Inherent Optical Properties ◽  
Good Consistency ◽  
The Vertical Distribution ◽  
Local Noon

The vertical distribution of irradiance in the ocean is a key input to quantify processes spanning from radiative warming, photosynthesis to photo-oxidation. Here we use a novel dataset of thousands local-noon downwelling irradiance at 490 nm (Ed(490)) and photosynthetically available radiation (PAR) profiles captured by 103 BGC-Argo floats spanning three years (from October 2012 to January 2016) in the world’s ocean, to evaluate several published algorithms and satellite products related to diffuse attenuation coefficient (Kd). Our results show: (1) MODIS-Aqua Kd(490) products derived from a blue-to-green algorithm and two semi-analytical algorithms show good consistency with the float-observed values, but the Chla-based one has overestimation in oligotrophic waters; (2) The Kd(PAR) model based on the Inherent Optical Properties (IOPs) performs well not only at sea-surface but also at depth, except for the oligotrophic waters where Kd(PAR) is underestimated below two penetration depth (2zpd), due to the model’s assumption of a homogeneous distribution of IOPs in the water column which is not true in most oligotrophic waters with deep chlorophyll-a maxima; (3) In addition, published algorithms for the 1% euphotic-layer depth and the depth of 0.415 mol photons m−2 d−1 isolume are evaluated. Algorithms based on Chla generally work well while IOPs-based ones exhibit an overestimation issue in stratified and oligotrophic waters, due to the underestimation of Kd(PAR) at depth.

Effects of Cu Dopant on Lattice and Optical Properties of ZnS Quantum Dots

2016 ◽  
Vol 16 (4) ◽  
pp. 3816-3820
Author(s):  
Lu Shuhua ◽  
Wang Aiji ◽  
Chen Tingfang ◽  
Wang Yinshu
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Dot ◽  
Blue Shift ◽  
Red Shift ◽  
Colloidal Nanocrystals ◽  
Long Tail ◽  
Low Concentrations ◽  
Cu Dopant ◽  
Cu Ions

Doped and undoped ZnS colloidal nanocrystals have drawn much attention due to their versatile applications in the fields of optoelectronics and biotechnology. In this paper, Cu doped ZnS quantum dots were synthesized via the simple thermolysis of ethylxanthate salts. The lattice and optical properties of the nanocrystals were then studied in detail. The quantum dot lattice contracted linearly between Cu concentrations of 0.2–2%, while it continued to contract more gradually as Cu concentrations were further increased from 4 to 6%, due in part to the Cu ions located on the surface of the ZnS lattice. Cu incorporation induces a long tail in absorption at long wavelengths. The PL spectrum shows a red shift at first, and then a blue shift with increases in Cu concentration. Cu doped at low concentrations (0.2–1%) enhanced the emission, while high Cu concentrations (2–6%) quenched emissions.

Triplet-State Electron Spin Resonance of Chlorophyll a and b Molecules and Complexes in PMMA and MTHF. I: Experimental Determination of Fine-Structure and Rate Constants

1978 ◽  
Vol 33 (1) ◽  
pp. 83-93 ◽  
Author(s):  
W. Hagele ◽  
D. Schmid ◽  
H. C. Wolf
Keyword(s):  
Triplet State ◽  
Chlorophyll A ◽  
Rate Constants ◽  
Resonance Field ◽  
Zero Field ◽  
Chlorophyll B ◽  
Low Concentrations ◽  
Spin Resonance ◽  
Chlorophyll A And B

The triplet state zero-field splittings and the rate constants for the population and depopulation of the triplet spin sublevels have been investigated for chlorophyll a and chlorophyll b in polymethylmethacrylate (PMMA) and methyltetrahydrofurane (MTHF) as a function of the concentration. In PMMA both chlorophyll a and chlorophyll b yielded only one ESR spectrum in the entire range of concentration which could be covered (1.5 × 10-5 - 1 × 10-3 mole/1). In MTHF the results were more complicated. At low concentrations (up to 103 mole/1) only one spectrum was observed, at higher concentrations additional spectra were detectable (all together two for chlorophyll a and five for chlorophyll b at 10-1 mole/1). The assignment of these spectra was facilitated by observing the "triplet resonance-field identity" which connects the resonancefield strengths for the canonical orientations of one particular species. Furthermore, the rate constants for some of these species could be determined.

Synthesis of chlorophyll-a derivatives possessing (un)substituted 131-exo-methylene moiety and their optical properties

2014 ◽  
Vol 55 (5) ◽  
pp. 1093-1096 ◽  
Author(s):  
Hitoshi Tamiaki ◽  
Shun Koizumi ◽  
Kazuki Tsuji ◽  
Yusuke Kinoshita ◽  
Tomohiro Miyatake
Keyword(s):  
Optical Properties ◽  
Chlorophyll A
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