Mapping the chlorophyll-a horizontal gradient in a cascading reservoirs system using MSI Sentinel-2A images

In this paper, the causes of the anomalous harmful algal bloom which occurred in the fall of 2020 in Kamchatka have been detected and analyzed using a long-term time series of heterogeneous satellite and simulated data with respect to the sea surface height (HYCOM) and temperature (NOAA OISST), chlorophyll-a concentration (MODIS Ocean Color SMI), slick parameters (SENTINEL-1A/B), and suspended matter characteristics (SENTINEL-2A/B, C2RCC algorithm). It has been found that the harmful algal bloom was preceded by temperature anomalies (reaching 6 °C, exceeding the climatic norm by more than three standard deviation intervals) and intensive ocean level variability followed by the generation of vortices, mixing water masses and providing nutrients to the upper photic layer. The harmful algal bloom itself was manifested in an increase in the concentration of chlorophyll-a, its average monthly value for October 2020 (bloom peak) approached 15 mg/m3, exceeding the climatic norm almost four-fold for the region of interest (Avacha Gulf). The zones of accumulation of a large amount of biogenic surfactant films registered in radar satellite imagery correlate well with the local regions of the highest chlorophyll-a concentration. The harmful bloom was influenced by river runoff, which intensively brought mineral and biogenic suspensions into the marine environment (the concentration of total suspended matter within the plume of the Nalycheva River reached 10 mg/m3 and more in 2020), expanding food resources for microalgae.

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First Results of Phytoplankton Spatial Dynamics in Two NW-Mediterranean Bays from Chlorophyll-a Estimates Using Sentinel 2: Potential Implications for Aquaculture

Remote Sensing ◽

10.3390/rs11151756 ◽

2019 ◽

Vol 11 (15) ◽

pp. 1756 ◽

Cited By ~ 4

Author(s):

Soriano-González ◽

Angelats ◽

Fernández-Tejedor ◽

Diogene ◽

Alcaraz

Keyword(s):

Chlorophyll A ◽

Spatial Dynamics ◽

Ebro Delta ◽

Band Ratio ◽

Environmental Forcing ◽

Shellfish Farming ◽

First Results ◽

Nw Mediterranean ◽

Sentinel 2A ◽

Sentinel 2

Shellfish aquaculture has a major socioeconomic impact on coastal areas, thus it is necessary to develop support tools for its management. In this sense, phytoplankton monitoring is crucial, as it is the main source of food for shellfish farming. The aim of this study was to assess the applicability of Sentinel 2 multispectral imagery (MSI) to monitor the phytoplankton biomass at Ebro Delta bays and to assess its potential as a tool for shellfish management. In situ chlorophyll-a data from Ebro Delta bays (NE Spain) were coupled with several band combination and band ratio spectral indices derived from Sentinel 2A levels 1C and 2A for time-series mapping. The best results (AIC = 72.17, APD < 10%, and MAE < 0.7 mg/m3) were obtained with a simple blue-to-green ratio applied over Rayleigh corrected images. Sentinel 2–derived maps provided coverage of the farm sites at both bays allowing relating the spatiotemporal distribution of phytoplankton with the environmental forcing under different states of the bays. The applied methodology will be further improved but the results show the potential of using Sentinel 2 MSI imagery as a tool for assessing phytoplankton spatiotemporal dynamics and to encourage better future practices in the management of the aquaculture in Ebro Delta bays.

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Chlorophyll-a and total suspended solids retrieval and mapping using Sentinel-2A and machine learning for inland waters

Ecological Indicators ◽

10.1016/j.ecolind.2020.106236 ◽

2020 ◽

Vol 113 ◽

pp. 106236 ◽

Cited By ~ 3

Author(s):

Mohammadmehdi Saberioon ◽

Jakub Brom ◽

Václav Nedbal ◽

Pavel Souc̆ek ◽

Petr Císar̆

Keyword(s):

Machine Learning ◽

Chlorophyll A ◽

Suspended Solids ◽

Total Suspended Solids ◽

Inland Waters ◽

Sentinel 2A

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Giám sát biến thiên mức độ phú dưỡng của hồ Hoàn Kiếm dựa vào hàm lượng Chlorophyll–a tính toán từ ảnh Sentinel–2A

Vietnam Journal of Hydrometeorology ◽

10.36335/vnjhm.2021(721).11-20 ◽

2021 ◽

Vol 721 (1) ◽

pp. 11-20

Author(s):

Nguyễn Thiên Phương Thảo ◽

Phạm Quang Vinh ◽

Nguyễn Thị Thu Hà ◽

Nguyễn Thùy Linh

Keyword(s):

Chlorophyll A ◽

Sentinel 2A

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Remote Sensing Detection of Algal Blooms in a Lake Impacted by Petroleum Hydrocarbons

Remote Sensing ◽

10.3390/rs14010121 ◽

2021 ◽

Vol 14 (1) ◽

pp. 121

Author(s):

Giovanni Laneve ◽

Milena Bruno ◽

Arghya Mukherjee ◽

Valentina Messineo ◽

Roberto Giuseppetti ◽

...

Keyword(s):

Microbial Community ◽

Chlorophyll A ◽

Petroleum Hydrocarbons ◽

Algal Blooms ◽

The State ◽

Satellite Systems ◽

Sentinel 2A ◽

Reference Measurements ◽

Available Information ◽

Dinoflagellate Bloom

The purpose of this study was to combine all available information on the state of Lake Pertusillo (Basilicata, Italy), both in the field and published, which included Sentinel-2A satellite data, to understand algal blooms in a lacustrine environment impacted by petroleum hydrocarbons. Sentinel-2A data was retrospectively used to monitor the state of the lake, which is located near the largest land-based oil extraction plant in Europe, with particular attention to chlorophyll a during algal blooms and petroleum hydrocarbons. In winter 2017, a massive dinoflagellate bloom (10.4 × 106 cell/L) of Peridinium umbonatum and a simultaneous presence of hydrocarbons were observed at the lake surface. Furthermore, a recent study using metagenomic analyses carried out three months later identified a hydrocarbonoclastic microbial community specialized in the degradation aromatic and nitroaromatic hydrocarbons. In this study, Sentinel-2A imagery was able to detect the presence of chlorophyll a in the waters, while successfully distinguishing the signal from that of hydrocarbons. Remotely sensed results confirmed surface reference measurements of lacustrine phytoplankton, chlorophyll a, and the presence of hydrocarbons during algal blooms, thereby explaining the presence of the hydrocarbonoclastic microbial community found in the lake three months after the oil spill event. The combination of emerging methodologies such as satellite systems and metagenomics represent an important support methodology for describing complex contaminations in diverse ecosystems.

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Retrieval and mapping of chlorophyll-a concentration from Sentinel-2 images in an urban river in the semiarid region of Brazil

Ambiente e Agua - An Interdisciplinary Journal of Applied Science ◽

10.4136/ambi-agua.2488 ◽

2020 ◽

Vol 15 (2) ◽

pp. 1

Author(s):

Alessandro Rhadamek Alves Pereira ◽

João Batista Lopes ◽

Giovana Mira de Espindola ◽

Carlos Ernando da Silva

Keyword(s):

Chlorophyll A ◽

River Mouth ◽

Water Quality Monitoring ◽

Semiarid Region ◽

Surface Reflectance ◽

Chlorophyll A Concentration ◽

In Situ Data ◽

Sentinel 2A ◽

Sentinel 2

Recently, the Poti river mouth region has experienced environmental impacts that resulted in a change of landscape in its dry season, highlighting the eutrophication and proliferation of phytoplankton, algae, cyanobacteria and aquatic plants. Considering the aspects related to water-quality monitoring in the semiarid region of Brazil from remote sensing, this study aimed to evaluate the performance of Sentinel-2A satellite data in the retrieval of chlorophyll-a concentration in Poti River in Teresina, Piaui, Brazil. The chlorophyll-a concentration retrieval and mapping methodology involved the study of the water surface reflectance in Sentinel-2A images and their correlation with the chlorophyll-a data collected in situ during the years 2016 and 2017. The results generated by the Chl-1, Ha et al. (2017), Chl-2, Page et al. (2018), and Chl-3, Kuhn et al. (2019) equations show the need for calibrating the algorithms used for the Poti River water components. However, the empirical algorithm Chl-2 shows a correlation has been established to identify the spatiotemporal variation of chlorophyll-a concentration along the Poti River broadly and not punctually. The spatial distribution of this pigment in maps derived from Sentinel-2A is consistent with the pattern of occurrence determined by the in situ data. Therefore, the MSI sensor proved to be a tool suitable for the retrieval and monitoring of chlorophyll-a concentration along the Poti River.

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Seagrass Cholorophyll-a, Biomass and Carbon Algorithms Based on the Field and Sentinel-2A Satellite Data at Karimunjawa Island, Indonesia

Science & Technology Indonesia ◽

10.26554/sti.2021.6.3.121-130 ◽

2021 ◽

Vol 6 (3) ◽

pp. 121-130

Author(s):

Agus Hartoko ◽

Yoan Teresia Sembiring ◽

Nurul Latifah

Keyword(s):

Chlorophyll A ◽

Satellite Data ◽

Leaf Morphology ◽

Dry Weight ◽

Mitigation Strategy ◽

Thalassia Hemprichii ◽

Halophila Ovalis ◽

Seagrass Biomass ◽

Sentinel 2A ◽

Chlorophyll A Content

Chlorophyll-a in seagrass biomass is functioned for the photosynthetic process and store the organic carbon in their biomass of the leaf, rhizome, and root. Ecologically has functioned as blue carbon in reducing global warming adaptation and mitigation strategy. The study aimed to explore seagrass species, chlorophyll-a content, biomass and carbon stock at Karimunjawa Island. Develop algorithms of the Sentinel-2A satellite data based on field seagrass chlorophyll-a, biomass and carbon and at Pokemon and Bobby beach Karimunjawa Island. Four species of seagrass found at Bobby and Pokemon beach are Holodule pinifolia with a density of 160.44 ind.m−2 , Enhalus acoroides with 26.22 ind.m−2, Halophila ovalis with 6.67 ind.m−2 and Thalassia hemprichii with 4.44 ind.m−2.The lowest seagrass chlorophyll-a is 5.854 mg.ml−1 found in H. pinifolia and the highest is 20.819 mg.ml−1found in E. acoroides at Pokemon beach. The range of seagrass chlorophyll-a at Bobby beach was 3.485 - 14.133 mg.ml−1 in T. hemprichii. The smallest individual biomass dry weight was found in T.hempirichii with 1.32 g.dry.weight per individu, and the biggest in E.acoroides with 6.98 g.dry.weight per individu. The highest seagrass biomass at Pokemon beach was in E. acoroides with 236.93 g.m−2 which has a wide leaf morphology and the lowest in H. pinifolia with 75.91 g.m−2 with the smallest leaf morphology. The range of seagrass biomass at Bobby beach is 97.62 - 264.48 g.m−2 which is dominated by T.hempirichii. The range of seagrass carbon was 109.63 - 136.82 gC.m−2at Pokemon beach, and in the range of 95.00 - 114.01 gC.m−2 at Bobby beach. Algorithm of seagrass chlorophyll-a = -36.308 (B3/B4)2 – 140.41(B3/B4) + 83.912 ; biomass = -7028.3 (B3/B4)2 + 14948 (B3/B4) – 7764.4; carbon = -17.529(B2/B3)2 + 143.82(B2/B3) – 5.3362 for Pokemon beach. Algorithm of chlorophyll-a = 455.02 (B2/B4)2 + 823.72 (B2/B4) + 375.48; biomass = -14699 (B3/B2)2 + 28395(B3/B2) – 13537; and carbon = - 0.001(B3/B4)2+ 0.209(B3/B4) - 10.203 for Bobby beach. The use of Band-2 (0.490 ????m), Band-3 (0.560 ????m) and Band-4 (0.665 ????m) Sentinel-2A satellite data in the development of seagras chlorophyll-a, biomass and carbon algorithm was found to be significant.

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