Spatiotemporal Evaluation of Eutrophication State in The Hammar Marsh Using A Satellite-Based Model

Water pollution is now a major threat to the existence of living beings. Accordingly, Water quality monitoring is an important activity toward restoring water quality. As wetland eutrophication is one of the essential ecosystem elements, devastation of this element is a significant issue. The Trophic State Index (TSI) provides information about trophic condition of water bodies. This paper aims to conduct spatiotemporal monitoring for the eutrophication of the west part of Al-Hammar Marsh for the period 2013-2020. To this end, a satellite-based TSI computation model was developed and implemented by using a series of OLI Landsat satellite images. The results showed that there was no improvement in the eutrophication state in the marsh, the percentage of the low class of TSI decreased in 2015 and 2018 to 7.9% and 2.6% and increased in 2017 and 2020 to 39.8%, and 56.3%. In general, the TSI was in the poor class in all the considered periods. Fluctuation of quantity and quality of the inflow prevents restoring the eutrophication of the marsh because this process requires stability in the levels of inundation above the critical limits for the water depth and periods. Therefore, it is necessary to find suitable alternatives to provide water drainage in quantities and quality that ensure the sustainability of the marsh ecosystem.

Determinação da Concentração de Clorofila-a por Sensoriamento Remoto no Reservatório de Chapéu d’Úvas (Mg), Brasil

Na atualidade, um grande impacto nos reservatórios de água doce é a eutrofização, que afeta diretamente o tratamento e uso da água para abastecimento público, navegação, fauna e flora aquática e impacto visual. A clorofila-a é um dos indicadores de estado trófico da água e pode ser determinada utilizando sensoriamento remoto. Desta forma, este estudo objetivou determinar a concentração de clorofila-a na barragem de Chapéu d’Uvas em Juiz de Fora (Brasil), um dos principais mananciais de abastecimento público da cidade. Através de um modelo utilizando imagens do satélite Sentinel-2 foi avaliado o comportamento espaço-temporal da concentração do componente, foi correlacionado com dados de pluviosidade, temperatura, evaporação e uso e ocupação do solo em torno da barragem. Também foi aplicado um modelo para determinar o índice de estado trófico, que apresenta o grau de trofia que o corpo hídrico se encontra, classificando Chapéu d’Uvas como estado mesotrófico. Os resultados se mostraram satisfatórios para a espacialização e análise temporal da concentração de clorofila-a, a correlação com os dados de evaporação nos permitiu observar uma compatibilidade direta com a concentração do componente e verificou-se valores de clorofila-a acima da média do reservatório nas regiões de entradas de água pelos riachos e próximos as margens com menos cobertura de vegetação.Determination of Chlorophyll-a Concentration from Remote Sensing in Chapéu d’Úvas Reservoir (State of Minas Gerais, Brazil) A B S T R A C TCurrently, one of the great impacts on the freshwater reservoirs is eutrophication, which directly affects the treatment and use of water for public water supply, navigation, aquatic fauna and flora and visual impact. Chlorophyll-a is one of the water trophic state indicators and it can be determined using remote sensing. Thus, this study aimed to determine chlorophyll-a concentration in Chapéu d’Uvas dam, in Juiz de Fora (Brazil), one of the main water sources of public water supply for the city. From a model that uses Sentinel-2 satellite images, the spatial-temporal behavior of that component concentration was evaluated and correlated with data regarding rainfall, temperature, evaporation, and soil use and occupation around the dam. A model was also applied to determine trophic state index, which presents the body of water trophic state, classifying Chapéu d’Uvas as mesotrophic state. The results were satisfactory regarding spatialization and temporal analysis of chlorophyll-a concentration. The correlation with evaporation data permitted us to observe a direct correspondence with the component concentration. Chlorophyll-a values higher than the reservoir average were found in creek inlets and near the shore with lower vegetal cover.Keywords: eutrophication, Sentinel-2, quality of water, inland waters, trophic state

Assessment of Water Quality Based on Trophic Status and Nutrients-Chlorophyll Empirical Models of Different Elevation Reservoirs

Water quality degradation is one of the most pressing environmental challenges in reservoirs around the world and makes the trophic status assessment of reservoirs essential for their restoration and sustainable use. The main aims of this study were to determine the spatial variations in water quality and trophic state of 204 South Korean reservoirs at different altitude levels. The results demonstrated mean total phosphorus (TP), chlorophyll-a (CHL-a), total suspended solids (TSS), organic matter indicators (chemical oxygen demand: COD; total organic carbon: TOC), water temperature (WT), and electrical conductivity (EC) remain consistently higher in the very lowland reservoirs (VLLR) than those in other altitudes, due to sedimentary or alluvial watersheds. The average TP and CHL-a levels in VLLR crossed the limit of the eutrophic water, symptomizing a moderate risk of cyanobacterial blooms. Empirical models were developed to identify critical variables controlling algal biomass and water clarity in reservoirs. The empirical analyses of all reservoir categories illustrated TP as a better predictor of CHL-a (R2 = 0.44, p < 0.01) than TN (R2 = 0.02, p < 0.05) as well as showed strong P-limitation based on TN:TP ratios. The algal productivity of VLLR (R2 = 0.61, p < 0.01) was limited by phosphorus, while highland reservoirs (HLR) were phosphorus (R2 = 0.23, p < 0.03) and light-limited (R2 = 0.31, p < 0.01). However, TSS showed a highly significant influence on water clarity compared to TP and algal CHL-a in all reservoirs. TP and TSS explained 47% and 34% of the variance in non-algal turbidity (NAT) in HLR. In contrast, the TP and TSS variances were 18% and 29% in midland reservoirs (MLR) and 32% and 20% in LLR. The trophic state index (TSI) of selected reservoirs varied between mesotrophic to eutrophic states as per TSI (TP), TSI (CHL-a), and TSI (SD). Mean TSI (CHL-a) indicated all reservoirs as eutrophic. Trophic state index deviation (TSID) assessment also complemented the phosphorus limitation characterized by the blue-green algae (BGA) domination in all reservoirs. Overall, reservoirs at varying altitudes reflect the multiplying impacts of anthropogenic factors on water quality, which can provide valuable insights into reservoir water quality management.

Trophic Status In Joto Reservoir, Lamongan

Waduk Joto merupakan waduk yang berada di Kabupaten Lamongan yang biasa digunakan oleh masyarakat sekitar untuk aktifitas sehari-hari. Selain itu aliran air waduk juga digunakan untuk kegiatan perikanan dan pertanian. Dalam pengelolaan suatu perairan yang lestari dan berkelanjutan diperlukan informasi dasar mengenai tingkat kesuburan perairan guna pemanfaatan yang tepat. Penelitian ini bertujuan untuk mengetahui kualitas air dan status kesuburan perairan di Waduk Joto Kabupaten Lamongan. Metode pengumpulan data menggunakan purposive random sampling pada tiga stasiun yaitu bagian inlet, tengah, dan outlet. Penentuan status kesuburan perairan berdasarkan perhitunganmenggunakan Carlson Trophic State Index (TSI). Pengambilan sampel air dilakukan dengan interval waktu satu bulan sekali selama 3 bulan pada bulan Desember 2020 sampai Februari 2021. Parameter yang diamati meliputi suhu, kecerahan, pH, salinitas, oksigen terlarut (DO), nitrat, total fosfat, klorofil-a. Hasil penelitian menunjukkan bahwa status kesuburan perairan Waduk Joto pada bulan Desember 2020 – Februari 2021 berdasarkan TSI Carlson termasuk dalam kategori perairan hipereutrofik dengan nilai sebesar 74. Disarankan untuk melakukan penelitian lanjutan pada musim yang berbeda untuk mengetahui status kesuburan perairan di musim kemarau.

Study of the degradation level influence of coastal zones on the water trophicity in lakes Turgoyak and Uvildy, Chelyabinsk region (Russia)

The man-made impact on hydro-ecological state of water-bodies affects every stage of water ecosystem formation. Such a load has certain patterns of spatial formation distribution of coastal geosystems with different stages of digression as a result of direct recreational impact on hydrological natural monuments Southern Urals - Lake Turgoyak and Lake Uvildy. The current paper researches a degradation level of the coastal zones of the Lakes Turgoyak and Uvildy (Russia). To prepare for measurements and measure recreational load, the methods of trial areas, transect, mathematical-statistical and registration-measuring methods were used. The level of digression at the test site was determined by an integral generalized assessment of fifteen characteristic criteria for anthropogenic transformation of geosystems on a five-point scale. The trophic status of the studied areas of the lakes was determined by the Carlson Trophic State Index (TSI). Determined that, landscape and recreational zones with various degrees of digression were formed around the lakes under the influence of dispersed recreational load. On the territory of camping sites located no further than 30-50 m from the water-bodies, the 4th-5th stage of recreational digression prevails. At a distance of 50-200 m from the lakes, there is a 2-3 stage of digression. At a distance of up to 100-150 m – the 3rd stage, and from 150 m – the 1-2 stage. Within recreation centers, spatial differences in recreational digression are expressed slightly, and geosystems are more often characterized by a 3-5 stage of digression. It is established that the littoral zooplankton is more diversity in those parts of the lake water area where there are optimal conditions for its development, the lowest recreational load and the lowest degree of digression.

Environmental Characterization of Two Ecologically Distinct Gangetic Oxbow Lakes Using Zooplankton Taxonomic Indices In Ecological Monitoring: A Comparative Approach

In recent years closed and seasonally open oxbow lakes and river floodplains are subjected to eutrophication due to disconnection from river that compromises the hydro-ecological functions. This requires systematic studies to assess the ecological health of the water bodies using different indices and suggest appropriate strategies to manage the resources. The zooplanktons are closely link with surrounding environment throughout their life cycles and change rapidly in their growth and population when changes occurs in the surrounding, hence act as potential indicator of eutrophication. The present study examined the assemblage pattern of zooplankton community and trophic state of two ecologically distinct oxbow lakes based on eco-hydrological characteristics and community structure of rotifers and planktonic crustaceans seasonally over a period of 2 years. Comprehensive trophic state index (mTSI), rotifer trophic state index (mTSIROT) and Crustacean based indices (TSICR) were used to assess the degree of eutrophication. The Kruskal-Wallis test confirmed the heterogeneity of the eco-hydrological factors between the oxbow lakes. A total of 68 zooplankton species were identified of which rotifers (69%), cladocerans (18%), copepods (3%), ostacods (3%) and protozoans (7%). Seasonal fluctuation of relative abundance and frequency of species in both lakes have been well presented. Both lakes showed transition from high meso-eutrophic to moderately eutrophic state with mTSI, mTSIrot and mTSIcr values of 54.90±11.71 and 56.95±15.64, 59.55±4.54 and 60.26±4.48, 55.79±4.76 and 60.00±4.03 in Khalsi (seasonally open) and Akaipur (closed) respectively. The Canonical Correspondence analysis (CCA) revealed water quality parameters comparison NO3-N, water temperature and pH have contributed more in enhancement of abundance of eutrophication indicator species Brachionus and Keratella. The TSIs values indicated a prompt aquaculture fisheries management measures like stocking of planktivorous fish (Labeo catla and Puntius sp.) for both the lakes before they reach in plunged state at which their restoration might become a challenge. An overview of worldwide use of rotifer and crustacean based indices in assessment of TSI has also been synthesized. The use of these zooplankton indices to evaluate the trophic status of the ecologically distinct lakes is highly recommended for water quality assessment and management. Based on this study strategies could be developed to plan and manage floodplain oxbow lakes for fisheries enhancement programme as well as as conservation of biodiversity.

Detection of chlorophyll fluorescence as a rapid alert of eutrophic water

An in-situ detection of chlorophyll fluorescence was used in an innovative manner to detect eutrophic water, and the results were compared with the Carlson's Trophic State Index (CTSI) indicators. Eutrophication was due to climate warming and anthropogenic activities. The turbidity and chromaticity showed a strong linear relationship (R2 = 0.85) of the Bi Lake in Taipei city. Both the swimming area and the bridge are popular with the general public and had the worst turbidity (35.80–44.00 NTU) and chromaticity (495.37–552.27 Pt). The CTSI had a stronger linear relationship with the phycocyanin (PC) concentration (R2 = 0.605) than with any other three CTSI factors like chlorophyll-a concentration, total phosphorus (TP) concentration, and transparency. The TP pollution had a potential to cause an increase in PC concentration found in this study (R2 = 0.86). The absorbances of the water samples represented the environment is PC (cyanobacteria) dominant in winter. The PC concentration in Bi Lake ranged from 75.55 to 80.24 μg/L and higher with lower water temperature. Measurement of in-situ chlorophyll fluorescence is similar to lab-scaled spectrophotometer (R2&gt;0.92). The real-time detection of PC concentration could be the basis of a rapid alert system to biological threats to waters.

Eutrophication Factor Analysis Using Carlson Trophic State Index (CTSI) Towards Non-Algal Impact Reservoirs in Taiwan

Carlson trophic state index (CTSI) has been commonly adopted to assess the eutrophication potential of reservoirs or lakes in water quality management. This study aims to analyze the influencing factors of CTSI-based eutrophication by using Pearson correlation analysis and principal component analysis (PCA) with long-term data from 2008 to 2019 on 21 drinking water reservoirs in Taiwan. The trophic state index (TSI) deviation indicates that most drinking water reservoirs in Taiwan, around 45.5% of statistical data fall into non-algal turbidity with surplus phosphorus, especially in the spring and winter season. Besides, there are about 78 % of total collected data show that TSI (Chl-a) is less than TSI (SD) due to the small particulate predominance. On the other hand, three TSI variables (Secchi depth (SD), total phosphorus (TP) and chlorophyll-a (Chl-a)) of CTSI exhibits insignificant correlation to each other in most cases. At such a condition, the probability of eutrophication (TSI>50) based on TSI (SD) is 63%, while it is only as low as 20% based on TSI (TP) and TSI (Chl-a). The influencing factors of eutrophication variables by suspended solids (SS) composition and turbidity have shown that the SD is strongly influenced by non-algal SS. The deviations of three TSI have shown that the highest algae-induced eutrophication potential occurs in the summer season. In addition, the TP is the most significant loading factor of algae-induced eutrophication for drinking water reservoirs. It is concluded that the CTSI has limited applicability to identify the trophic status of drinking water reservoirs in Taiwan in the presence of sustainable non-algal turbidity comparative Chl-a that completely represents algal growth potential (AGP).

Positive effects of COVID-19 lockdown on river water quality: evidence from River Damodar, India

The global economic activities were completely stopped during COVID-19 lockdown and continuous lockdown partially brought some positive effects for the health of the total environment. The multiple industries, cities, towns and rural people are completely depending on large tropical river Damodar (India) but in the last few decades the quality of the river water is being significantly deteriorated. The present study attempts to investigate the river water quality (RWQ) particularly for pre- lockdown, lockdown and unlock period. We considered 20 variables per sample of RWQ data and it was analyzed using novel Modified Water Quality Index (MWQI), Trophic State Index (TSI), Heavy Metal Index (HMI) and Potential Ecological Risk Index (RI). Principal component analysis (PCA) and Pearson’s correlation (r) analysis are applied to determine the influencing variables and relationship among the river pollutants. The results show that during lockdown 54.54% samples were brought significantly positive changes applying MWQI. During lockdown, HMI ranged from 33.96 to 117.33 with 27.27% good water quality which shows the low ecological risk of aquatic ecosystem due to low mixing of toxic metals in the river water. Lockdown effects brought river water to oligotrophic/meso-eutrophic condition from eutrophic/hyper-eutrophic stage. Rejuvenation of river health during lockdown offers ample scope to policymakers, administrators and environmentalists for restoration of river health from huge anthropogenic stress.

A Universal Fuzzy Logic Optical Water Type Scheme for the Global Oceans

The classification of natural waters is a way to generalize and systematize ocean color science. However, there is no consensus on an optimal water classification template in many contexts. In this study, we conducted an unsupervised classification of the PACE (Plankton, Aerosols, Cloud, and Ocean Ecosystem) synthetic hyperspectral data set, divided the global ocean waters into 15 classes, then obtained a set of fuzzy logic optical water type schemes (abbreviated as the U-OWT in this study) that were tailored for several multispectral satellite sensors, including SeaWiFS, MERIS, MODIS, OLI, VIIRS, MSI, and OLCI. The consistency analysis showed that the performance of U-OWT on different satellite sensors was comparable, and the sensitivity analysis demonstrated the U-OWT could resist a certain degree of input disturbance on remote sensing reflectance. Compared to existing ocean-aimed optical water type schemes, the U-OWT can distinguish more mesotrophic and eutrophic water classes. Furthermore, the U-OWT was highly compatible with other water classification taxonomies, including the trophic state index, the multivariate absorption combinations, and the Forel-Ule Scale, which indirectly demonstrated the potential for global applicability of the U-OWT. This finding was also helpful for the further conversion and unification of different water type taxonomies. As the fundamental basis, the U-OWT can be applied to many oceanic fields that need to be explored in the future. To promote the reproducibility of this study, an IDL®-based standalone U-OWT calculation tool is freely distributed.