Eutrophic Conditions Research Articles

Exploration and implication of green macroalgal proliferation in the Nanhui-east-tidal-flat: an investigation of post-reclamation mudflat wetlands

The Nanhui-east-tidal-flat (NETF), the largest marginal shoal in the Yangtze River of China, is significantly impacted by human activities. Prior research has not detected the presence of green macroalgae in the NETF, nor has it explored the effects of reclamation on the distribution of macroalgae. However, in 2021, a small-scale aggregated attached algal mats emerged in the NETF, potentially signaling the onset of a green tide and necessitating vigilant monitoring. Morphological and molecular biological identification analysis revealed that all collected green macroalgae were attributed to a single dominant species, Ulva prolifera, characterized by broad blades and prominent air bladders, colonizing various substrates. The attached U. prolifera exhibited continuous growth from March to May 2021, peaking at a wet weight of 373.6229 g/m² and a dry weight of 72.7904 g/m² on May 1, 2021, within the accessible sampling period. The rapid proliferation of the “opportunistic” Ulva was facilitated by high-level eutrophication and favorable environmental conditions. Furthermore, six potential germplasm sources of U. prolifera are summarized. The dominance of Ulva in the intertidal zone often indicates high eutrophication and deteriorating ecological conditions. With long-term reclamation and repeated ecological restoration projects, the intertidal vegetation is subjected to a vicious cycle of growth and destruction. Therefore, it is important to recognize that U. prolifera germplasm (macroalgae and micropropagules) will persist over the long term, and mudflats with monotonous and eutrophic habitats are highly likely to experience future large-scale algal blooms. Notably, a small-scale floating green tide was observed in the sea area near NETF in July 2023, and such concerns are not unfounded. This study conducts foundational scientific research on the attached green tide algae, a type of research that is relatively scarce in other marine areas. Most studies tend to initiate foundational research only after the outbreak of green tides, lacking early background data from the marine environment, thus rendering this study of significant reference value. Concurrently, this study emphasizes that field surveys remain an essential approach for conducting foundational scientific research on green tide algae in the NETF region, with the need to select appropriate research methods based on the occurrence and development of algal mats, as required by the situation. Importantly, this study reflects the stability of marine ecosystems as a prerequisite for modern ocean management and services, provides new perspectives on the occurrence and development of green tides, and highlights potential ecological risk factors that should be considered in the implementation of intertidal construction projects.

A Previously Unknown Building Structure in Ancient Olympia (Western Peloponnese, Greece) Revealed by Geoarchaeological Investigations and Its Interpretation as a Possible Harbor

The ancient site of Olympia is located on the northern fringe of the Basin of Makrisia at the confluence of the Kladeos and Alpheios rivers (western Peloponnese, Greece) and was used as a venue for the Panhellenic Games from Archaic times until the 4th century AD. Geophysical prospection (frequency domain electromagnetic induction and electrical resistivity tomography) was carried out as a basis for detailed geoarchaeological investigations. In doing so, we identified a previously unknown building structure adjacent to the Altis, the inner part of the sanctuary at Olympia. Situated south of the Southwest Thermae, this structure measures at least 100 m (WSW-ENE) by 80 m (NNW-SSE). Its external orientation is in line with the orientation of the Southwest Thermae and the Leonidaion. We retrieved sediment cores from 17 different locations in combination with high-resolution direct push sensing from inside the newly found structure. All cores revealed distinct units of organic-rich limnic sediments dominated by clay and fine silt. Geochemical and micropaleontological analyses of selected sediment samples indicate highly eutrophic conditions, as evidenced by elevated phosphorous concentrations and the dominance of the ostracod species Cyprideis torosa, which is able to live under low-oxygen conditions. Moreover, molecular biomarker analyses show a significant input of lipid fecal markers, implying strong anthropogenic pollution. Further, the limnic sediments include numerous charcoal remains and abundant diagnostic artifacts such as ceramic fragments and building material. Radiocarbon dating documents that these limnic conditions persisted within the building structure from at least the 5th century BC to the 6th century AD. The identified building structure lies in the immediate proximity to the Lake of Olympia, which was recently found to have existed from the mid-Holocene to the Medieval period. Its characteristic filling with fine-grained sediments and multiple indications for a strongly polluted and heavily used standing water environment let us hypothesize that it was possibly used as a harbor installation. A harbor at ancient Olympia could have been used to reach the sanctuary by boat and to transport goods of all kinds.

Water quality and eutrophication status of the Zarivar Wetland (Iran)

Wetlands are critically impacted by a variety of pollutants, primarily due to their position at the terminus of both surface and subsurface water flows. This study aims to assess the eutrophication status of Zarivar Wetland, situated in Kurdistan Province, Iran. To evaluate the eutrophication levels, the research employed the Iranian Water Quality Index for Surface Water Resources-Conventional Parameters (IRWQISC) and the Carlson’s Trophic State Index (TSI) during two sampling periods in July and September 2021. The findings indicate that in July, the wetland exhibited an upper-mesotrophic condition, with an average Carlson index value of 52.2, while in September, it transitioned to both upper-mesotrophic and eutrophic conditions, reflected by an average Carlson index value of 60.17. The zoned map of the eutrophication index identified domestic sewage from Marivan city as a significant contributor to elevated eutrophication levels in the southeastern region. Additionally, runoff from irrigated agricultural lands, orchards, and domestic wastewater from surrounding villages contributed to heightened eutrophication in the northeastern and eastern areas of the wetland. A comparative analysis of water quality between July and September 2021 revealed IRWQISC values ranging from 3.57 to 9.72 in July and from 2.63 to 4.72 in September, categorizing them as relatively good and good, respectively. To safeguard Zarivar Wetland, it is recommended to implement measures that prevent livestock waste discharge into the wetland, manage urban and rural sewage systems, control agricultural runoff, and optimize fertilizer application practices.

Using the Forel-Ule index (FUI) to track the water quality of subsidence water bodies across the life cycle of coal mining in eastern China.

The water quality and associated ecological risks in subsidence water bodies formed by underground coal mining are an increasing global concern. However, long-term water quality changes in these subsidence water bodies, especially across different spatial regions, remain poorly understood. This paper, by mapping the Forel-Ule index (FUI) a key indicator of water color, using Landsat datasets to reveal the dynamic evolution of water quality in 402 subsidence water bodies in the Huang-Huai-Hai Plain of eastern China from 1990 to 2020, covering their life cycle from formation to extinction. We identified three types of subsidence water bodies, including growing (14.4%), stable (35.1%), and shrinking (50.5%), almost all of which were found to exhibit eutrophic conditions. The findings revealed a blue-shift trend, indicative of improved water quality, was observed in nearly half (45.3%) of the water bodies. During mining, water quality was generally poor with higher average FUI values, but gradually improved at an average rate of -0.09yr⁻1. FUI values experienced a brief period of stability before deteriorating post-mining, with an average rate of 0.05yr⁻1. Our study provides valuable insights into the governance of subsidence water bodies in coal mining areas by revealing large-scale, long-term trends in water quality evolution.

Environmental triggers and ecological implications of a harmful algal bloom in the northern Arabian/Persian Gulf: Insights into the driving forces and consequences.

The Arabian/Persian Gulf, a marginal sea of the northern Indian Ocean, has been significantly impacted by human activities, leading to a rise in harmful algal blooms (HABs). This study investigates the summer blooming of an ichthyotoxic phytoflagellate Chattonella marina var. antiqua and associated fish-kill in Kuwaiti waters, connecting the events to a previous dust storm and eutrophication status in the coastal waters of the Northern Arabian Gulf (NAG). Pre- and post-fish-kill sampling revealed significant differences in Chattonella cell densities and environmental conditions, with cell densities reaching 435×103 cells L-1 in the post-fish-kill period. Chattonella structural properties and environmental conditions reported significant differences between the fish-kill and non-fish-kill areas. Apparent Oxygen Utilization patterns suggested higher organic carbon remineralization in areas with dense Chattonella density, suggesting the bloom's potential to promote heterotrophic activities in the water column. The toxicity levels and structural properties of Chattonella positively correlated with deteriorating water quality. We postulate that a severe dust storm that occurred two months before the bloom played a critical role in enhancing the nutrient availability, which, supplemented with an allochthonous nutrient supply and a genetically programmed, temperature-dependent excystment of Chattonella cysts, initiated the vegetative cell growth of Chattonella culminating in a bloom. It is postulated that the increased water temperatures, reduced dissolved oxygen solubility, elevated metabolic rates in fish, and the ichthyotoxins secreted by the bloom impaired fish respiratory mechanisms and caused fish mortality. Thus, this study explains the possible long-term effects of summer dust storms in the northern Arabian Gulf, as understanding the role of environmental mechanisms triggering HABs is vital to comprehend their ecological implications in coastal marine systems.

Evaluation of spatial variation and nutritional status of environmental quality in the surface seawater from fishing harbours of Hainan island

To investigate the nutrient distribution characteristics and the eutrophication status of the main fishing ports in Hainan Province, this study analyzed the 2021 seawater quality indicators, including biochemical oxygen demand (BOD5), chemical oxygen demand (COD), chlorophyll a (Chl a), ammonia nitrogen (NH4-N), nitrite nitrogen (NO2-N), nitrate nitrogen (NO3-N), and soluble active phosphate (DIP). The single-factor contaminant index method was employed to evaluate the water quality, revealing that the levels of COD, BOD5, and DIP surpass the national seawater quality standards for Type IV. The eutrophication index (EI) of the different fishing ports ranges from 2.38 to 56.29, indicating a high level of eutrophication.

Probable Record of Paleocene - Eocene Thermal Maximum in Southwestern Nigeria: Indications from Nannofossils of FA-1 Borehole, Eastern Benin Basin.

The Paleocene – Eocene Thermal Maximum (PETM) interval has been reported in several calcareous nannofossil studies from Paleogene basins around world including the Southern Tethys basins of North Africa. The Southern Tethys basins are believed to be connected to the Eastern Benin Basin through the Trans – Saharan Seaway during the Paleogene. Based on these reports, we carried out a biostratigraphic and paleoclimatic analyses of the calcareous nannofossils recovered from 25 ditch cutting samples in the FA-1 borehole to investigate possible record of the PETM in the Eastern Benin Basin, Southwestern Nigeria. The samples yielded characteristic Paleocene – Eocene calcareous nannofossils species (Coccolithus pelagicus, Coccolithus formosus, Chiasmolithus solitus, Sphenolithus moriformis, Pontosphaera plana, Pontosphaera multipora, Lophodolithus mochioporus, Lophodolithus nanscens, Neochiastozygus perfectus and Zeugrhabdotus sigmoides) and the Maastrichtian species, Arkhangeskiella cymbiformis. The assemblages allow the recognition of CC 22 (Maastrichtian) and NP 4 – NP 6 (early – late Paleocene) nannofossil zones. The relatively abundant occurrences of the genus Coccolithus and Sphenolithus in the carbonate interval of borehole suggest prevailing oligotrophic, warm water condition. The barren interval succeeding the peak nannofossil abundance at sample 159 m coincides with the onset of continuous clastic sedimentation in the FA-1 borehole. This is believed to have resulted from the shoaling of the Calcite Compensation Depth (CCD) and increased clastic input occasioned by the climatic and ocean water perturbations of the PETM interval. The emergence of the genus Pontosphaera (Pontosphaera plana and Pontosphaera multipora) at depth 87 m above the barren interval suggest a return to cooler, mesotrophic to eutrophic water condition after the drastic temperature rise and oligotrophic waters of the PETM. Key-words - Calcareous nannofossils, Paleocene - Eocene, Benin Basin, Thermal Maximum.

Environmental Assessment Using Phytoplankton Diversity, Nutrients, Chlorophyll-a, and Trophic Status Along Southern Coast of Jeddah, Red Sea

The objective of this study is to better identify the state of eutrophication of coastal waters along the southern coast of the city of Jeddah in the Red Sea. Thirty-six samples from surface seawater were collected during the spring and autumn of 2021. Water temperature, pH, salinity, dissolved oxygen (DO), nutrients, and chlorophyll-a (Chl-a) content were examined as a guide of water quality indicators. The present data revealed low levels of Chl-a content (in the range of 0.11–0.24 µg L−1). The average concentrations of DIN (dissolved inorganic nitrogen) forms follow the order NO3-N > NH4-N ~ NO2-N (representing about 11.4–29.4% of the total nitrogen). To investigate the trophic status and water quality, numerical indicators were applied to the results of the analysis of chemical variables (NH4-N, NO3-N, and PO4-P) and the biological analysis (Chl-a) in the aqueous environment within the study area. These indicators are simplified based on the specialist, the non-specialist, the decision-maker, and the one responsible for managing the coastal areas. We also obtain through this method a single numerical value that expresses the state of the coastal waters. According to the analysis of phosphorus and nitrogen data and a trophic index (TRIX), the study area’s trophic status was determined as oligotrophic, due to low nutrient concentrations in the seawater. The current study identified a total of 58 species of phytoplankton comprised four classes in the investigated areas; Bacillariophyceae was the dominant algal class (Diatoms 30 species), followed by Chlorophyceae (9 species), Dinophyceae (11 species), and Cyanophyceae (8 species). Seasonally, spring recorded the highest value of total phytoplankton, recording a value of 251 × 103 cells/L with a percentage of 61%, while autumn recorded the lowest value of 186 × 103 cells/L with a percentage of 39%. Phytoplankton classes can be arranged in order of prevalence as follows: Bacillariophyceae >> Dinophyceae > Chlorophyceae > Cyanophyceae.

Geospatial Assessment of Trophic Status From a Dam Under Significant Agricultural Drainage at the Mid-Anatolia, Türkiye

The population of Anatolia is continuously growing and developing and it is under the deep influence of global warming. It is increasingly evident that more fresh water will be needed for drinking, irrigation and domestic use. This study aims to assess the water quality and trophic status of a dam (Bayramhacılı dam lake) under excessive agricultural irrigation threat using spatial and multivariate statistical analysis. In the study, the periodic changes in the eutrophic state of the dam lake were determined using global index categories, Carlson Trophic Status Index (CTSI = 66.7), Burns Trophic Level Index (BTLI = 6.4), and Shu Trophic State Index (STSI = 65.6). The two periodical averages of total phosphorus (TP), total nitrogen (TN), biological oxygen demand (BOD), (chemical oxygen demand (COD) and chlorophyll a (Chl_a) concentrations, which serve as an indicator of anthropogenic nutrient input, were determined to be 0.23, 31.28, 1.83, 8.99 and 48.1 µg/L, respectively. Trophic index distribution maps demonstrate that the dam’s surface water displays considerable alterations, particularly during the dry season. This evidence supports the implementation of a local management model that addresses the issue of eutrophication. It is therefore imperative that on-site measures are taken without delay.

Effectiveness analysis of surface reservoirs environmental monitoring methods in conditions of their eutrophication by agricultural facilities (review)

The high level of anthropogenic impact on the soils of arable lands and pastures has led to their inability to retain and decompose pollutants, including biogenic substances, transported with water. At the same time, agricultural facilities deserve special attention, which on the one hand are the largest water consumers worldwide, and on the other hand make a significant contribution to the biogenic pollution of surface waters. Due to the stable biogenic saturation of reservoirs, there is a threat of a widespread increase in phytoplankton biomass, which significantly affects the quality of water resources. Despite the existing measures to combat this phenomenon, the issue of water bodies environmental monitoring is open in conditions of eutrophication. The article provides a brief description of the most unfavorable agricultural facilities in terms of biogenic load on reservoirs. The features of the biogenic saturation mechanism of the aquatic environment from agricultural territories are considered. The article highlights the main methods of environmental monitoring of the aquatic environment, provides a brief description of their effectiveness in conditions of eutrophication, and provides an overview of innovative methods and technical solutions in the field under consideration. The author focuses attention on the need to create integrated environmental monitoring systems for water bodies that combine the useful properties of its three main methods (physico-chemical, biological and remote), as well as taking into account the process of eutrophication, including from agricultural facilities. The development of such complexes will expand the functionality, improve the quality and efficiency of environmental monitoring of surface waters located near agricultural facilities.

Assessing Temperature Change Impact in the Wake of Ongoing Land Use Change: A Case Study at Lake Dianshan

Climate change exerts both direct and indirect influences on the eutrophication of surface water ecosystems in various ways. This study aimed to evaluate the impact of temperature fluctuations on trophic levels through various interdisciplinary coupling analysis methods after land use change, which including water and sediment sample analysis, hydraulic model, remote sensing, and historic data analysis. For the historical analysis, six satellite images of Lake Dianshan were examined to assess algal bloom occurrences and the coverage of Eichhornia crassipes from 2013 to 2023. The correlation between trophic indicators and temperature was analyzed using statistical methods. For the monthly analysis, a total of 27 sediment samples and 54 water samples collected from Lake Dianshan were assessed to determine how seasonal temperature variations influence eutrophication status. The trophic indicators have higher concentration at inlet sampling sites compared to outlet sites, which validated the potential external pollution source. The trophic level of Lake Dianshan is influenced not only by climate change but also significantly by urban human activities. The management of eutrophication has substantially improved the water quality of Lake Dianshan over the past few decades. Furthermore, increasing temperatures demonstrate a positive correlation with the proliferation of cyanobacteria, particularly in urban areas.

Assessment of ecological status of Damsa Dam (Nevşehir, Türkiye) using trophic classification indexes, geospatial and statistical techniques

In this study, the water quality and trophic status of Damsa reservoir were evaluated using spatial and multivariate statistical analysis. When the thematic spatial distribution maps created for each parameter were analysed, it was determined that the water quality of Damsa Dam was class I water (very good) in terms of temperature, pH and dissolved oxygen and class III water (moderate) in terms of total N concentration. In the study, the changes on eutrophic status were analysed by global index categorisations and it was determined that Carlson trophic status index was CTSI=66.6, Burns trophic level index was BTLI=6.2 and Shu trophic status index was STSI=64.7. The results showed that Damsa Reservoir can reach the limits of ‘eutrophic’ according to CTSI classification scale, ‘eutrophic’ according to STSI classification scale and ‘hypereutrophic’ according to TLI classification scale. For this reason, the water quality of Damsa reservoir should be monitored continuously in certain periods and necessary interventions should be made in case of pollution.

Effects of Trophic State on the Composition and Distribution of Bacteria in the Surface Sediments of Lake Taihu

ABSTRACT1. The trophic state of water significantly affects the structure of bacterial communities in sediments. The direct and indirect impacts of trophic state, along with trophic‐induced changes in the properties of organic matter, on the composition and distribution of bacteria in sediments, remain largely unknown.2. We collected surface sediments from 21 sites across five areas of Lake Taihu, the third largest freshwater lake in China. These sites represented a range of trophic states from mesotrophic to moderately eutrophic. We investigated how trophic state influences bacterial composition and distribution in the surface sediments of Lake Taihu.3. Proteobacteria, Firmicutes and Bacteroidetes were the most abundant phyla identified in the DNA sequences of surface sediments from the sampling sites in Lake Taihu, regardless of the water trophic state. The relative abundance of Proteobacteria and Firmicutes in the surface sediments increased with trophic level index (TLI) of the water column. In contrast, the relative abundance of Bacteroidetes, Acidobacteria and Fibrinobacteria decreased with increasing TLI. The α‐biodiversity of the sediment bacterial community in Lake Taihu did not vary significantly among different water trophic states. However, surface sediments from sites with varied trophic states exhibited different groups of bacteria that were either specifically present or in higher relative abundance.4. Several factors influenced the sediment bacterial communities in Lake Taihu, including sediment total nitrogen, sediment total phosphorus, sediment organic carbon, δ13C and trophic state. However, the primary influencing factors varied between sites and trophic states. For mesotrophic states, sediment organic carbon was the most important factor, while for moderately eutrophic states, trophic state was the most significant factor.5. Our findings provide evidence for both the direct and indirect influences of water trophic state on the composition and distribution of bacteria in sediments.

Marine ecosystem extent and condition pilot accounts for Finland

Ecosystem accounting provides a standardised framework for evaluating the economic value of ecosystems to society. Following the international accounting standard, System of Environmental Economic Accounting – Ecosystem Accounting (SEEA EA), we present first marine ecosystem extent pilot accounts for Finland, based on three habitat classification systems: the Marine Strategy Framework Directive (MSFD), the EU Habitats Directive (HD) and the IUCN Red List of Ecosystems (RLE). We assess their condition using indicators from the Water Framework Directive, which measure ecosystem quality through biological, ecological and physico-chemical parameters. We found that MSFD habitats have the largest extent, exceeding the areas covered by HD and RLE habitats. A large portion of the assessed habitats, particularly in the inner archipelago and shallow areas close to shore, were in poor condition, reflecting the eutrophication status of coastal waters. We identify considerable challenges in reporting marine ecosystem extent and condition accounts, which most likely recur across (European) countries. For instance, MSFD habitats are rather coarse for accurately reporting ecosystem extents, potentially overlooking declines in ecosystem condition, while HD habitats cover only a subset of habitats. RLE habitats provide more ecological detail, although they may be less compatible with classifications used in other countries. Our research provides a baseline for future ecosystem accounts and emphasises the need for improved data and methods to enhance the accuracy and comparability of marine ecosystem assessments. Additionally, we discuss the compatibility of SEEA EA with EU policy reporting requirements, the spatial scale of reporting ecosystem extents and condition and highlight the limitations of current habitat classifications in representing the full diversity of marine ecosystems. The findings underscore the importance of integrating multiple habitat classification systems, development of crosswalks between habitat classifications and monitoring frameworks to ensure comprehensive and accurate ecosystem accounts.

Spatiotemporal Assessment of Water Quality and Quantity of the Kaptai Lake at Rangamati, Bangladesh - An Approach of Remote Sensing, Field Investigation and Laboratory Analysis

Monitoring water quality and quantity is essential for sustainable water resource management. This study investigates changes in the extent and water quality of Kaptai Lake using remote sensing, field measurements, and laboratory analysis. Analysis of Landsat TM/OLI images from 1989, 2000, 2010, and 2021 shows that the lake's water extent ranges from 380 km² (in 2010) to 435 km² (in 2021), with an average of 407.5 km². The extent of water decreased by approximately 3% from 1989 to 2010 and increased by about 5% from 2010 to 2021 due to changing rainfall patterns, dam operations, sedimentation, and land use changes. Seasonal variations in chlorophyll-a concentration and turbidity, analyzed using Sentinel 2B images from 2022 and 2023, indicate mesotrophic to eutrophic conditions and higher turbidity in post-monsoon. The study found that nutrient enrichment from untreated sewage, agricultural runoff, and algal growth affect chlorophyll-a levels, while development activities, excessive rainfall, and sedimentation influence turbidity. Linear regression analyses show strong positive correlation between field obtained and image derived values both for chlorophyll-a (R2 0.621) and turbidity (R2 0.698). Physico-chemical parameters such as pH, EC and temperature have been measured in the field and hydrochemical parameters including, cations and anions have been measured by laboratory analysis to assess the contemporary water quality status. The average values for pH, EC and temperature are 7.55, 119.85 µS/cm and 22.17 °C respectively. The cationic dominance in the studied segment of the Lake is in the order of Ca2+ > Na2+ > Mg2+>K+ > Fe2+ >Mn2+. On the other hand, the anions are in the order of HCO3- > SO42- > Cl- > NO3-. All the physico-chemical parameters of the lake water fall within the Bangladesh Drinking Water Limit (BDWL) and are not linked to chlorophyll-a and turbidity variations. The findings of this study can help mitigate the deterioration of Kaptai Lake by addressing water quality and extent issues, promoting effective and sustainable lake management strategies. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 13(1), 2024, P 121-139

Eutrophication-Driven Changes in Plankton Trophic Interactions: Insights from Trade-Offs in Functional Traits.

Understanding how plankton trophic interactions, particularly phytoplankton nutrient uptake and zooplankton grazing, respond to eutrophication is important for maintaining aquatic ecosystem functions and developing effective mitigation strategies. Phytoplankton exhibit trade-offs in functional traits between growth rate and antipredation defense, thereby regulating these trophic interactions. However, the combined effects of eutrophication and such trait-based regulation on plankton communities and interactions remain poorly understood. In the present study, we investigated these effects by integrating trait-based mechanistic modeling and field observations in China's eutrophic Pearl River Estuary. Our model predicted that the species with the weakest defensive capacities dominated under nutrient-poor conditions. As eutrophication increased, a concave growth-defense trade-off favored species with high growth rates and strong defense capacities, whereas a convex trade-off curve favored species that were either the least or the most well-defended. High grazing pressure accelerated these shifts. In the estuary, similar patterns emerged in the relative abundance of different phytoplankton species along a gradient of the nitrogen to phosphorus ratio (N:P), indicating changes from high nutrient uptake and low grazing under oligotrophic conditions to eutrophic conditions, in which some phytoplankton face considerable grazing pressure despite high nutrient uptake, whereas others grow slowly with less grazing pressure. These results enhance our understanding of trait-based plankton interactions in eutrophic bodies of water and provide support for more effective conservation and management strategies.

A hybrid ecological evaluation of the fisheries in changing climate: case study from a peri-urban tropical wetland of Kolkata, Eastern India.

The degradation of peri-urban wetlands has been a significant consequence of urban development and climate change. The present study discovered the decadal changes in land cover and climate impact on Raja Wetland, revealing significant alterations from 2011 to 2021. The analysis indicates substantial reductions in agricultural land (36.36%), fallow land (30.90%), water spread areas (10.14%) and surrounding wetlands (18.06%). Conversely, settlements, terrestrial vegetation and aquatic macrophytes increased by 19.77%, 3.39% and 1.16%, respectively. The primary driver of wetland shrinkage was urban expansion leading to a decrease in wetland area from 43.39ha in 2011 to 38.99ha in 2021. Climate data from 1991 to 2020 show a decreasing trend in annual rainfall (τ = - 0.274, p = 0.035) and an increasing trend in annual temperature (τ = 0.339, p = 0.009), with significant warming particularly during the monsoon months. The wetland's physicochemical attributes fluctuate seasonally, with eutrophic conditions prevailing (TSI range: 61.41-80.36). Notably, fish diversity is impacted by the dominance of the invasive species Oreochromis niloticus, which constitutes 89.31% of the catch. The established planktonic indicator genera of organic pollution were found to be abundant throughout the study period. These, combined with urban pollution and eutrophication, have led to a reduction in native fish species and overall aquatic health. The study highlights the urgent need for conservation measures to address the ecological imbalance and restore wetland resilience amidst ongoing climate and anthropogenic pressures. The communication also proposes various recommendations for the recovery and sustainable future use of wetland fisheries in the context of ongoing changes.

Desarrollo puberal y estado nutricional en adolescentes de la Unidad Educativa San Pedro Pascual, Ibarra 2023

BMI is a recommended indicator to assess nutritional status in adolescents; however, puberty should be considered during adolescence. The objective of the study was to determine the pubertal development and nutritional status of adolescents from the San Pedro Pascual Educational Unit, Ibarra. This research, which was descriptive, quantitative, and cross-sectional in nature, focused on a population of 256 adolescents aged 12 to 15 years, with a sample size of 71. Exclusion criteria: students whose parents did not sign the informed consent. The study encompassed a range of variables, including nutritional status (BMI/age and height/age), sociodemographic characteristics, and pubertal development. A variety of instruments, such as surveys, Tanner booklets, and anthropometry forms, were used to gather comprehensive data. The use of the anthropometric software WHO Anthro Plus, along with data analysis in Microsoft Excel 360 and EPIINFO 7.2.5, ensured the thoroughness and accuracy of our methodology. The results indicate that the mean of the anthropometric indicators indicate normality, adequate height (99%), and 63% have a eutrophic state; however, women have higher percentages of overweight and risk of overweight; men are located in pubertal stages 1, 2 and 3; while women are in stages 3 and 4, mostly. Conclusions: There are no similarities in BMI by stage or age in any sex; however, in women in the more mature stages 3 and 4, more similar BMI values ​​prevail because the BMI in women increases as sexual maturation increases, regardless of chronological age; although, in men with a higher Tanner stage, the BMI averages decrease.

Changes in the Antioxidant System of Germinating Seeds and Sprouts of Pea with the Use of Micellar-Substrate Extract of Oyster Mushrooms

The reactions of the antioxidant system (AOS) of daily germinating seeds and 8-day-old pea seedlings cultivated using 10% and 100% aqueous extract from spent oyster mushroom straw substrate (hereinafter extract) were studied. The mother liquor was taken for 100% extract after its preparation, and the 10% was obtained by diluting the mother liquor. The plants were grown in oligotrophic hydroponic conditions and in eutrophic conditions on gray forest soil. The activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), expression of SOD-1, CAT-1, POD genes, and the content of low molecular weight antioxidants (NMAO): ascorbate, phylloquinones, and free proline were studied as the main indicators of the AOS reaction. The inhibitory effect of 10% and 100% extract on the activity of SOD and CAT, but not on the activity of POD in daily germinating seeds, has been shown. At the same time, the content of mRNA transcripts of the SOD-1 and POD genes decreased only slightly in seeds cultivated with 100% extract, in the remaining experimental groups the level of gene expression did not differ from the control. The content of ascorbate in all experimental groups did not differ from the control, and phylloquinones and free proline were less than in the control. In the leaves of 8-day-old seedlings cultivated in a hydroponic medium, in all experimental groups, the activity of AOS enzymes, the expression of their coding genes and the content of phylloquinones and free proline did not differ from the control. At the same time, the ascorbate content was higher. In plants cultivated in soil using a 10% extract, all EPA indicators did not differ from the control. In plants grown using 100% extract, the activity of SOD, the expression level of the SOD-1 gene, the content of ascorbate and free proline were higher, and the remaining indicators did not differ from the control. Thus, the extract at the initial stages of germination inhibited the AOS of peas, followed by restoration (in oligotrophic conditions) and enhancement (in eutrophic cultivation conditions) of its work.

Management implications following the reconstruction of the small and shallow Lake Mustijärv (Estonia)

Lake Mustijärv was reconstructed by sediment removal following an almost complete siltation. Here we evaluate challenges and opportunities for the management of the lake. We focused on the stream discharging to the lake (i.e., external loading), sediment retention in accumulation basins (i.e., internal processes) as well as the ecosystem-level response to stressors based on biological variables (phyto- and zooplankton, macrophytes, fishes and zoobenthos). Urban and agricultural inputs elevated ammonium and total phosphorus concentrations in the lake, challenging lake reconstruction efforts. Sediment transport highly increased the risk of faster filling of the lake, associated with upstream streambed excavation. Sediments trapped at the accumulation basins release nutrients that enhance eutrophication. We, however, observed a rapid recovery in fish, macrophytes, and zoobenthos, despite the significant disturbances. Lake Mustijärv is in eutrophic condition, reflected by phytoplankton (Pseudanabaena, Closteriopsis dominance) and zooplankton (Keratella, Polyarthra dominance) composition. To improve lake water quality will require controlling external nutrient inputs, underlining the importance of better coordinated activities between the local (lake restoration) and regional (catchment use) scales.