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Prediction of daily chlorophyll a concentration in rivers by water quality parameters using an efficient data driven model: online sequential extreme learning machine

Alizamir Meysam, Heddam Salim, Kim Sungwon, Gorgij Alireza Docheshmeh, Li Peiyue, Ahmed Kaywan Othman, Singh Vijay P.

Acta Geophysica

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2021

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Vol. 69, no. 6

2339--2361

EN

One of the main concerns of environmental and ecological managers for rivers, lakes, reservoirs, and marine ecosystems is developing a reliable and efficient predictive model for chlorophyll a concentration. In this study, the online sequential extreme learning machine, M5 Prime tree, multilayer perceptron artificial neural network, response surface methodology, and multivariate adaptive regression spline models were investigated for daily chlorophyll a concentration prediction by assessing the relations between Chl-a and several water quality parameters, including water temperature, pH, specific conductance, and turbidity. Different scenarios based on TE, pH, SC, and TU were defined. Also, this study evaluated the influence of periodicity input as the last scenario to obtain more accurate predictions of Chl-a values. Daily data measured for 2009–2019 from USGS no. 14207200 and USGS no. 14211720 stations were used. For assessing the prediction performance of the proposed techniques, three different objective indicators were employed, namely RMSE, R2 , and NSE. Moreover, the Taylor diagram was employed for evaluating the accuracy and generalization capability of the applied models for the prediction of Chl-a. Results indicated that OS-ELM with input parameters of TE, pH, SC, TU, Y (year), M (month), and D (day) showed higher accuracy in predicting Chl-a with RMSE of 3.151, NSE of 0.798, and R of 0.894 for USGS no. 14207200 and with RMSE of 0.907, NSE of 0.820, and R of 0.912 for USGS no. 14211720 than the other models, respectively. Additionally, MLPNN ranked as the second best method for the estimation of Chl-a values at both stations. As an interesting point, it was quite evident that adding periodicity as an input parameter could significantly enhance the performance of all models in predicting the daily Chl-a concentration at both stations. Results proved that OS-ELM models can be a reliable tool for the prediction of the Chl-a values in aquatic environments, benefiting ecological and environmental management, and algal bloom control.

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Remote sensing reflectance of Pomeranian lakes and the Baltic

Ficek D., Zapadka T., Dera J.

Oceanologia

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2011

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No. 53 (4)

959-970

EN

The remote sensing reflectance R_rs, concentrations of chlorophyll a and other pigments C_i, suspended particulate matter concentrations C_SPM and coloured dissolved organic matter absorption coefficient αCDOM(λ) were measured in the euphotic zones of 15 Pomeranian lakes in 2007-2010. On the basis of 235 sets of data points obtained from simultaneous estimates of these quantities, we classified the lake waters into three types. The first one, with the lowest αCDOM(440 nm) (usually between 0.1 and 1.3 m-1 and chlorophyll α concentrations 1.3 < Ca < 33 mg m-3), displays a broad peak on the reflectance spectrum at 560-580 nm and resembles the shape of the remote sensing reflectance spectra usually observed in the Baltic Proper. A set of Rrs spectra from the Baltic Proper is given for comparison. The second lake water type has a very high CDOM absorption coefficient (usually αCDOM(440 nm) > 10 m-1, up to 17.4 m-1 in Lake Pyszne; it has a relatively low reflectance (Rrs < 0.001 sr-1) over the entire spectral range, and two visible reflectance spectra peaks at ca 650 and 690-710 nm. The third type of lake water represents waters with a lower CDOM absorption coefficient (usually αCDOM(440 nm) < 5 m-1) and a high chlorophyll a concentration (usually Ca > 4 mg m-3, up to 336 mg m-3 in Lake Gardno). The remote sensing reflectance spectra in these waters always exhibit three peaks (Rrs > 0.005 sr-1): a broad one at 560-580 nm, a smaller one at ca 650 nm and a well-pronounced one at 690-720 nm. These Rrs(λ) peaks correspond to the relatively low absorption of light by the various optically active components of the lake water and the considerable scattering (over the entire spectral range investigated) due to the high SPM concentrations there. The remote sensing maximum at λ 690-720 nm is higher still as a result of the natural fluorescence of chlorophyll a. Empirical relationships between the spectral reflectance band ratios at selected wavelengths and the various optically active components for these lake waters are also established: for example, the chlorophyll a concentration in surface water layer Ca = 6.432 e4.556X, where X = [max Rrs (695 ≤λ≤720) - Rrs(? = 670)] / max Rrs (695 ? ? ? 720), and the coefficient of determination R^2 = 0.95.

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Remote sensing of vertical phytoplankton pigment distributions in the Baltic: new mathematical expressions. Part 1: Total chlorophyll a distribution

Ostrowska M., Majchrowski R., Stoń-Egiert J., Woźniak B., Ficek D., Dera J.

Oceanologia

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2007

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No. 49 (4)

471-489

EN

This article is the first in a series of three describing the modelling of the vertical different photosynthetic and photoprotecting phytoplankton pigments concentration distributions in the Baltic and their interrelations described by the so-called non-photosynthetic pigment factor. The model formulas yielded by this research are an integral part of the algorithms used in the remote sensing of the Baltic ecosystem. Algorithms of this kind have already been developed by our team from data relating mainly to oceanic Case 1 waters (WC1) and have produced good results for these waters. But their application to Baltic waters, i.e., Case 2 waters, was not so successful. On the basis of empirical data for the Baltic Sea, we therefore derived new mathematical expressions for the spatial distribution of Baltic phytoplankton pigments. They are discussed in this series of articles. This first article presents a statistical model for determining the total concentration of chlorophyll, a (i.e., the sum of chlorophylls a+pheo derived spectrophotometrically) at different depths in the Baltic Sea Ca(z) on the basis of its surface concentration Ca(0), which can be determined by remote sensing. This model accounts for the principal features of the vertical distributions of chlorophyll concentrations characteristic of the Baltic Sea. The model's precision was verified empirically: it was found suitable for application in the efficient monitoring of the Baltic Sea. The modified mathematical descriptions of the concentrations of accessory pigments (photosynthetic and photoprotecting) in Baltic phytoplankton and selected relationships between them are given in the other two articles in this series (Majchrowski et al. 2007, Woźniak et al. 2007b, both in this volume).

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Production of transparent exopolymer particles (TEP) in the nitrogen fixing cyanobacterium Anabaena flos-aquae OL-K10

Surosz W., Palińska K.A., Rutkowska A.

Oceanologia

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2006

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No. 48 (3)

385-394

EN

The aim of the study was to measure the transparent exopolymer particles (TEP) concentration in cultures of Anabaena flos-aquae OL-K10 and to determine the relationship between the quantity of particles produced and the light intensity, the age of the culture and the presence of nitrogen in the culture medium. This is the first time TEP production has been investigated in the Nostocales, an order of nitrogen-fixing phytoplankton species. The results showed that TEP production depends on the presence of nitrogen in the culture medium. The longer the culture is grown, the higher the correlation between its TEP content and its chlorophyll a concentration.

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Phytopsammon and phytoplankton of land/water ecotone of mesotrophic lake in the Polesie region (Eastern Poland)

Czernaś K., Krupa D.

Polish Journal of Ecology

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2003

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Vol. 51, nr 2

183-194

EN

In the years 1996-1997 (in July and September) a species composition as well as a productivity of phytopsammon (eupsammon and hydropsammon) and phytoplankton were investigated in a land/water ecotone of mesotrophic lake. The phytopsammon was characterized by a higher number of species and higher algae abundance than that of phytoplankton. The highest values of gross primary production and chlorophyll a concentration were obtained for eupsammon, while the lowest ones were obtained for phytoplankton. A big similarity of eupsammon and hydropsammon and a considerable diversity between eupsammon and phytoplankton was proved.

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Phytoplankton as eutrophication indicator in the Gulf of Gdańsk water

Niemkiewicz E., Wrzołek L.

Oceanological Studies

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1998

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Vol. 27, No. 4

77-92

EN

The present survey presents the results of phytoplankton number and biomass measurements and also chlorophyll a contents in marine water. The investigations were started in autumn1994 and continued in summer 1995 along six coastal profiles in the Gulf of Gdańsk. The paper provides the current condition of the phytoplankton - the first link in the food chain in a water body biocenosis. The research confirmed also the early 80s findings as to the changed structure of phytoplankton domination where flagellates dominated in terms of number and dinoflagellates - in terms of biomass.