A Study on Spatiotemporal Downscaling Methods for Chlorophyll-a Concentration in Taihu Lake Based on Remote Sensing Data from Sentinel-2 MSI and COMS-1 GOCI

Water, Journal Year: 2025, Volume and Issue: 17(6), P. 855 - 855

Published: March 17, 2025

Taihu Lake is a large lake with high levels of eutrophication. Cyanobacterial outbreaks significantly affect the ecological environment and socioeconomic development. The chlorophyll-a (Chl-a) concentration, which crucial for monitoring eutrophication, can be obtained through remote sensing inversion, random, sudden, complex changes impose stringent requirements on scale. However, single images often fail to meet both temporal spatial resolution Chl-a monitoring. This study took as research object, combined COMS-1 GOCI (1 h/500 m resolution) Sentinel-2 MSI (5 d/10 inverted data, developed precorrection-based spatiotemporal downscaling method (PC-STDM). After eliminating systematic bias, model used weighting (TWD) regression trend assessment (TRAD) methods downscale improving inversion data from 5 d 1 h. verification resulted in an average R2 0.87 between after adaptive correction. A comparison measured yielded maximum fitting coefficient 0.98, verifying credibility model. downscaled concentration detailed hourly development trends, providing support water quality area.

Language: Английский

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The functional diversity of phytoplankton depends on the type of ecosystem and the seasonal period in areas affected by residues from the biggest Brazilian mining disaster

Published: April 3, 2025

1. Nine years ago, the southeastern region of Brazil experienced largest mining disaster (in Lower Doce River Basin), which impacted several natural ecosystems. The relationships between functional diversity phytoplankton and environmental conditions provide evidence this community's responses to anthropogenic impacts. Thus, we aim identify main factors influencing considering three types ecosystems two distinct seasonal periods. It is expected that distribution traits will be influenced by light availability, nutrient metal concentrations, grazing pressure. 2. Sampling was conducted October 2018 September 2021 in shallow lakes deep floodplain. Functional indices were measured based on seven traits, including volume, silica demand, heterocyst presence, mixotrophy capacity, aerotopes flagela life form. 3. RLQ models highlighted can used as indicators variation region. Deep exhibited higher due lower eutrophication conditions, contamination, greater availability. In River, increase during dry season suggested an attenuation pressures, improvement conditions. 4. Our results showed a dependence type environment these environments experience effects according seasonality. Additionally, demonstrated resource reduced pressure sustained phytoplankton. 5. We emphasize importance aspects tool biomonitoring areas strongly activities.

Language: Английский

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Phytoplankton in Deep Lakes of the Dinaric Karst: Functional Biodiversity and Main Ecological Features

Plants, Journal Year: 2024, Volume and Issue: 13(16), P. 2252 - 2252

Published: Aug. 14, 2024

Phytoplankton is a polyphyletic group of organisms that responds rapidly to environmental conditions and provides reliable response changes, making it good ecological indicator for water quality monitoring. However, gradient almost essential relationship between pressure impact. In low-gradient environment, ingenuity required outsmart the limitations commonly used linear relationship. Here, we examine changes in biomass functional biodiversity by analysing larger data sets (2013–2022) six ecologically diverse, natural, deep Croatian karst lakes with low nutrient gradients using nonlinear correlation coefficients multivariate analyses 209 samples. We found phytoplankton was most strongly influenced nutrients, salinity alkalinity, while light availability total nitrogen biodiversity. An additional analysis TN:TP ratio revealed oligotrophic Lake Vransko nitrogen-limited, Kozjak Prošće are phosphorus-limited. This further clarified nutrients despite gradient. The complex this study new perspective predicting structure succession successful management under apparent anthropogenic climate change.

Language: Английский

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Nanopatterns on silica scales of Mallomonas (Chrysophyceae, Stramenopiles): Unraveling UV resistance potential and diverse response to UVA and UVB radiation

Journal of Phycology, Journal Year: 2024, Volume and Issue: 60(5), P. 1256 - 1272

Published: Sept. 16, 2024

Abstract Mallomonas thrive primarily in freshwaters and dominate plankton communities, especially oligotrophic waters. The cells have a siliceous cell covering of regularly arranged scales. Despite their ecological importance, the intricate structure evolutionary significance silica scales are still unexplored. We investigated nanopatterns on hypothesized that they may play role UV shielding. UVA UVB exposure experiments were performed with 20 species, categorized into four groups based nanopattern (plain‐scaled, meshed, striated, papilliferous group); fifth group consisted species extremely thick, robust regardless nanopattern. revealed thick associated enhanced resistance, suggesting protective role. No significant differences response observed among groups, except for meshed group, which showed lower likely due to less regular pattern shield. In conclusion, scale case, composed sufficiently silicified scales, provides effective protection freshwater environments, particular increased radiation, thickness plays Contrary expectations, size phylogeny do not strongly predict resistance. study highlights diverse responses , but further studies needed understand scales/nanopatterns adaptations species.

Language: Английский

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