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Limnology: Lake and River Ecosystems
... Water temperature Water temperature is a key ecological factor influencing chemical and biological processes in aquatic ecosystems [32,33]. It varies according to seasons and human activities [34,35]. ...
... Total hardness reflects the concentration of calcium and magnesium in water, influencing water quality and aquatic ecosystems [32]. It results from the dissolution of minerals (limestone, dolomite) and anthropogenic inputs (industrial discharges, agriculture) [60]. ...
... Calcium (Ca 2+ ) and magnesium (Mg 2+ ) are essential elements for aquatic ecosystems, playing key roles in biological processes (shell formation, photosynthesis) and geochemical processes (mineral precipitation) [32,59]. Their concentrations are influenced by the dissolution of minerals (limestone, dolomite) and anthropogenic activities (industrial discharges, agriculture) [60][61][62]. ...
... Among many consequences of these stressors, disruptions of dissolved oxygen (DO) sources and sinks can significantly impact freshwater habitats and influence biodiversity, biogeochemical cycles and overall environmental health (Franklin, 2014;Killgore and Hoover, 2001;North et al., 2014). Primary producers, such as phytoplankton, serve as a key 40 source of DO via photosynthesis, whereas respiration by heterotrophic organisms acts as major sinks that consume DO (Heddam, 2014;Wetzel, 2011). However, DO concentrations are not solely regulated by biological activity, but also by atmospheric exchange and environmental factors such as temperature, light availability and nutrient levels (Benson et al., 1979;Odum, 1956;Stumm and Morgan, 1995). ...
... With rising temperatures and longer daylight in spring, biological activity became more prominent and led to moderate to high DO concentrations (Figure 2d; Figure S2d, S3) (Wetzel, 2011). The associated δ¹⁸ODO values indicated 245 enhanced photosynthetic activity, as they gradually shifted from atmospheric equilibrium toward less positive values ( Figure 3d; Figure S5). ...
... These results align well with previous findings published by Liška et al. (2021), who reported almost stable nitrate concentrations in the Danube over the past decades without 355 noticeable peaks from potential point sources. One possible explanation is that primary producers rapidly absorb and utilize available nutrients and prevent their accumulation in measurable concentrations (Joint et al., 2001;Wetzel, 2011). This mechanism could explain the observed productivity patterns, despite minimal variance in nutrient levels and may particularly account for phosphate that is rapidly taken up by primary producers. ...
Dissolved oxygen (DO) is a fundamental indicator for water quality and ecosystem health, particularly in the context of anthropogenic impacts and climate change. This study presents the first large-scale dataset of DO concentration combined with its stable oxygen isotope ratios (expressed as δ18ODO), particulate organic carbon concentrations (POC) and respiration/ photosynthesis (R/P ratios) from five seasonal campaigns along the entire Danube River in 2023 and 2024. Our findings reveal pronounced seasonal DO dynamics driven by temperature, biological activity and hydrodynamic conditions. During spring and summer, enhanced photosynthesis increased DO up to 0.40 mmol/L with δ18ODO values down to +12.1 ‰ and POC up to 0.25 mmol/L in two highly productive river sections. The strong correlation between δ18ODO and POC further confirms the dominant influence of primary producers (i.e., photosynthetic organisms) in a river section where a reduced slope led to slower flow and lower turbulence. Notably, δ18ODO values were significantly lower than those expected for atmospheric equilibrium (+24.6 ‰ ± 0.4 ‰), a pattern rarely documented in large river systems. In contrast, tributary inflows from the Tisa and Sava rivers diluted biomass and organic material inputs and led to declines in DO and POC. By late summer, intensified respiration reversed photosynthetic signals, led to the lowest DO concentrations down to 0.16 mmol/L and raised δ18ODO up to +23.7 ‰, particularly in the Sava River. In fall, DO levels partially recovered despite continued respiration, while in winter, oxygen input from the atmosphere became the dominant control with minimal biological influences. Overall, this study provides new insights into dynamic interplays between oxygen sources and sinks across the river continuum over seasons. These new insights underscore the need for continuous DO monitoring, particularly in late summer when oxygen levels can become critically low. Understanding these interactions can help to establish efficient aqueous ecosystem management and conservation strategies in the face of environmental and climate change.
... reflecting a dominant influence of seasonal cycles over local factors . Seasonal variability in pH could be related to factors such as increased photosynthesis by aquatic plants and phytoplankton in the dry season coinciding with the upwelling period in Senegal (Roy, 1992;Diankha, 2018), which consumes CO₂ and slightly increases pH (Wetzel, 2001). On the other hand, during the rainy season, freshwater inputs from rainfall and runoff could affect pH by diluting carbonates or introducing acidic organic matter (Howarth et al., 2002). ...
... Nitrates are the final products of the nitrogen cycle, formed by the oxidation of nitrites by nitrifying bacteria. Higher concentrations are therefore expected, whereas nitrites, intermediates in the nitrogen cycle, are generally unstable and present in low amounts (Wetzel, 2001). Low nitrite concentrations indicate active nitrification, where ammonium (NH4 + ) is effectively converted to nitrates via nitrites. ...
The Sangomar Marine Protected Area (MPA), located approximately 50 km from the Sangomar oil field, has raised concerns regarding the potential impact of oil activities on its resources. This study aims to determine the quality of the MPA's waters prior to the commencement of oil exploitation. Samples were collected at three locations of ecological importance and accessibility (Bakina, Sofna, and Djiffer) during both the dry and wet seasons over a two-year period (2023-2024). The study found strong seasonality for most of the parameters studied, with pH remaining relatively stable throughout the year, while significant seasonal variations were recorded for dissolved oxygen, salinity, and temperature. Concentrations of mineral elements, notably nitrates, phosphates, and ammonium, also showed fairly marked seasonal fluctuations. These elements are below the environmental standards for water quality set by international bodies. The results of this study demonstrate that the waters of the Sangomar MPA are of good quality overall. The study will provide a reference point for future assessments of the impact of oil exploitation activities on the Sangomar MPA.
... Lakes play a pivotal role in providing ecosystem services (Janssen et al., 2021;Wetzel, 2001) while simultaneously being highly vulnerable to human activities (Rao et al., 2024;Shi et al., 2024). Therefore, intensive and continuous water quality monitoring is a key requirement for effective water resource management and conservation Jiang et al., 2020;Zhang et al., 2024). ...
... An additional point is at the inlet point of Zala River. This sampling strategy, with a transect running along the lake axis and a station at the major river inflow, was empirically designed to capture the main gradients and representativeness of the overall lake conditions (Wetzel, 2001). For the six stations, there are 2369 records in total for the 40 years since 1984. ...
Chlorophyll-a (Chl-a) is one of the critical water quality indicators that shows the eutrophication status of aquatic ecosystems. As the largest lake and a well-known attraction in middle Europe, Lake Balaton contributes 70% or more of local economy through tourism, while also maintaining a unique biodiversity. Therefore, long-term monitoring of water quality is essential for its effective management. With the longest global environmental record and a preferable spatial resolution, the satellite constellation Landsat is used for retrieving Chl-a in this study. However, the common low-frequent in-situ samplings and ~16-day revisit of Landsat have limited both the quality and applicability of Landsat to Chl-a retrieval. Initially, we trained both linear and several machine learning models using matchups between in-situ measurements and satellite data from Landsat 4-9 missions during 1984 and 2023. To address the imbalanced data problem, which lacks high concentration samples due to the rare blooming events, we extend the time tolerance, incorporate temporal information, which connotes the phenology information, and apply an oversampling technique during the training process. Validated on Lake Balaton, which has a spatiotemporal amplitude of Chl-a concentration ranging from 5 to 260 µg/L since 1980s, Random Forest model has the best accuracy, which shows an R-square 0.86 and RMSE 8.16 μg/L. The oversampling technique improves the accuracy by 9.5% than the non-oversampled. Leveraging all strategies improves overall accuracy by 21%. The result also shows a reasonable trade-off via increasing the number of matchups 3 to 8 times by extending the time tolerance from the same day to 3 days regardless of the high variability of Chl-a due to the sinking and floating movement of algae. The enhancement framework can be applied to other lakes, especially for lakes with coarse samplings and wide Chl-a fluctuations. We present an open-source online tool for historical and real-time Chl-a mapping, designed for both experts and the public. With customizable code for global lakes, results are continuously showcased on the HUN-REN Balaton Limnological Research Institute's website and social media.
... The ratio of total nitrogen to total phosphorus (TN: TP) is a widely used indicator for assessing limiting nutrients in surface waters, as described by Wetzel. (2001). The TN: TP ratios and their corresponding categories are based on the classifications by Downing and McCauly. (1992) and Yang et al. (2008), are presented in (Table 5). ...
... The Nutrient Pollution Index (NPI) ranged from no pollution to high pollution at Ourkiss Dam, whereas at Babar Dam, the NPI fluctuated from no pollution to moderate pollution. This variation is attributed to agricultural activities, particularly the application of nitrogen-and phosphorus-based fertilizers, which progressively increase the concentrations of these compounds in both the water and soil (Wetzel, 2001;Manahan, 2011). The primary sources of nitrogen and phosphorus compounds in groundwater and surface waters are anthropogenic activities, including fertilizer use, animal feed operations, municipal wastewater, sewage sludge, and septic tanks (Tokatli, 2014). ...
... Environmental reconstruction based on lake sediments is an important tool for understanding the ontogeny of ecosystems across multiple spatial and temporal scales (Birks and Birks, 1980;Bradley, 2015;Delcourt and Delcourt, 1991;von Post, 1933;Von Post, 1946). Lakes are aquatic ecosystems that integrate dynamic interactions between the geosphere, hydrosphere, atmosphere, and biosphere (Saulnier- Talbot, 2016;Wetzel, 2001). Lake sediments serve as archives of time-structured environmental variability and can be used to trace paleoenvironmental variability because they contain evidence of prevailing environmental conditions, both within the lake and in its surrounding catchment (Cohen, 2003;Last et al., 2001). ...
... Thus, this axis enables differentiation between highly productive and anoxic systems toward the negative extreme, and less productive and oxygen-rich sites toward the positive extreme (Franco-Gaviria et al., 2020). These two characteristics are closely related, as production of abundant organic matter leads to oxygen consumption via respiration in the water column, and poorly oxygenated conditions promote organic matter preservation in sediments (Cohen, 2003;Meyers and Lallier-vergès, 1999;Wetzel, 2001). The NMDS2 model indicates that organic geochemistry is statistically influenced by vegetation seasonality (NDVI ssn ; Figure 6). ...
Lake sediment composition depends on the environmental context where sediments are produced, transported, and deposited. Factors involved in sedimentary processes imprint specific signatures on sediments, thus providing evidence on the environmental context at the time of deposition. The interaction of the involved factors and processes, however, results in complex signals that in some instances are difficult to interpret. Here, we explore and quantify the relationships between commonly analyzed attributes of lake sediments and the geological, climatic, and ecological context of the corresponding catchment basins. For this purpose, we analyzed the geochemical composition and modern pollen spectra of 132 lakes, and characterized each locality in terms of climate, topography, vegetation cover, geology, and human activities in the catchment basin. The studied lakes included areas of Mexico, Guatemala, Belize, Honduras, and El Salvador, thus encompassing Mesoamerica, a culturally defined region. Multivariate statistics and regression techniques were used to assess the quantitative relationships between environmental and sedimentary variability. According to our results, the inorganic sediment chemistry is strongly influenced by basin geology, reflecting the contrasting nature of karstic versus other sediments. Conversely, the organic components are likely controlled by local factors, such as lake trophic status. Pollen assemblages reflect the regional biogeographic gradient from temperate to tropical vegetation with a strong modulation by topographic and climatic gradients. Our study confirms that whereas pollen spectra reflect regional conditions, sediment geochemistry captures local variability, highlighting the importance of a multiproxy approach for conducting paleoenvironmental reconstructions.
... This data is valuable for scientific research, enriching our understanding of aquatic ecology, hydrology, and biogeochemical cycles, and informing the development of environmental models and theories. Overall, monitoring and analyzing physiochemical parameters is essential for protecting and sustaining water resources for both the environment and human communities (Chapman, 1996;Wetzel, 2001). To evaluate the water environment, ecosystem, hydrochemistry, and ecology as well as to restore water quality, it is essential to monitor the physicochemical water quality parameters (Sarkar et al., 2016;Whitehead et al., 2018;Islam et al., 2019). ...
This study evaluates the seasonal variations in the physiochemical parameters of Ganga River and Bhimsen Pond water in Kanpur, India, during the pre-monsoon, monsoon, and post-monsoon seasons. Water samples were collected and analyzed for parameters such as pH, temperature, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), salinity, chloride, and nitrate concentrations. The results showed significant seasonal fluctuations in both water bodies, with more pronounced variations in the pond water due to its closed-system nature. The pH of the Ganga River was found 8.1 a notable increase during the monsoon season, while the pond water maintained a consistently higher pH 8.6. Temperature dropped significantly post-monsoon in both water bodies. Electrical conductivity decreased during the monsoon, highlighting the dilution effect of rainwater, with the pond showing a higher sensitivity to mineral content changes. Dissolved oxygen levels increased in both water bodies during the monsoon 6.3 in river and 6.83 mg/l in pond, reflecting enhanced aeration. TDS concentrations dropped significantly, particularly in the Ganga River, indicating a dilution effect. Salinity and nitrate concentrations also decreased during the monsoon, with pond water showing higher baseline concentrations, likely due to agricultural runoff and limited water exchange. Comparative analysis indicated that the pond water exhibited greater variability in physiochemical parameters, which is attributed to the impact of surface runoff and reduced natural flushing mechanisms. This study provides valuable insights into the water quality dynamics of the Ganga River and Bhimsen Pond, contributing to a better understanding of their ecological health and the effects of seasonal changes on water quality.
... Geology, as one of the mandatory descriptors in lake classification systems (System A and B), governs soil structure and subsequently influences the water chemistry of the basin in which a lake resides (Wetzel, 2001). For instance, lakes situated on limestone-dominated bedrock exhibit elevated levels of calcium carbonate, which enhance water hardness and pH buffering capacity (Schindler et al., 1980). ...
In the study of 70 lentic systems across Türkiye, the influence of alkalinity on phytoplankton assemblages was
evaluated in five alkalinity groups (I: 〈 140, II: 140–200, III: 200–300, IV: 300–600, V: 〉 600 mg l
-1 CaCO3) as a
proxy for geological variation. The analysis revealed that species composition varied with increasing alkalinity,
with certain species favoring higher alkalinity levels and exhibiting higher alkalinity optima. Species richness
(alpha diversity) was highest in Group I, while total species richness (gamma diversity) exhibited a consistent
decline as alkalinity increased, from Group I to Group V. In contrast, the highest phytoplankton biovolume was
observed in Group V. In addition to alkalinity, other environmental factors including electrical conductivity, total
nitrogen, total phosphorus, and pH were found to significantly influence the distribution of dominant species,
variations in species composition, alpha diversity, and phytoplankton biovolume across different alkalinity
groups. The PHYTO-TR index demonstrated that groups I, II, and III exhibited a higher proportion of high and
good ecological quality systems compared to those in higher alkalinity ranges, making the index more effective in
assessing the ecological status of these systems. While total phosphorus concentrations play a critical role in
determining trophic status, variations in the assimilation of different carbon sources by species in response to
alkalinity changes significantly affect the distribution, composition, biovolume, alpha, and gamma diversity of
phytoplankton and, consequently, the trophic status of lentic systems. Therefore, alkalinity directly impacts
phytoplankton, underscoring its importance as a key parameter in determining phytoplankton-based lake types.
... The recovery of organic nitrogen species has been reviewed for example by Weerakoon et al. (2023). One well-known consequence of excessive nitrogen release to water bodies is eutrophication; NH 4 + has a higher eutrophication potential than NO 3 − when nitrogen is the nutrient in shortest supply (Wetzel, 2001). ...
Approximately 312 billion m 3 of municipal wastewater is generated worldwide annually containing ~16.6 million tonnes of nitrogen which could meet ~17 % of the global agricultural demand. Nitrogen recovery from wastewater would thus be economically significant, improve security of supply for fertilizers, prevent eutrophication of water bodies, and curb the large carbon footprint of synthetic nitrogen fertilizer production. Currently, nitrogen recovery from wastewater is not a common practice and the conventional nitrogen removal process via microbial nitrification/denitrification causes nitrogen to be lost into the atmosphere. This review provides an overview of ammonium and nitrate recovery via adsorption technology from a techno-economic perspective. An adsorption process can be used in combination with other techniques (e.g., ammonia stripping , membrane separation, struvite precipitation, or microbial assimilation) as a pre-concentration method. The most studied adsorbents are zeolites, biochars, activated carbons, and ion-exchange resins where the highest reported adsorption capacities in a flow-through process aiming for nitrogen recovery are ~80 mg/g for ammonium and ~360 mg/g for nitrate. The few existing full-scale plants, economic assessments, and life-cycle analyses point out that adsorption-based nitrogen recovery can achieve lower costs, smaller environmental impact, and higher treatment efficiency than the status quo. Thus, adsorption technology could be an important part of the toolbox when shifting towards a circular economy of nitrogen.
... Streams, as critical components of human society and natural ecosystems, provide essential services, such as water supply, habitat for aquatic organisms, and flood regulation [1][2][3]. However, stream ecosystems have come under increasing pressure from human activities at both local and global scales [4][5][6]. ...
Land use and land cover changes driven by urbanization and agricultural expansion have increasingly degraded the ecological health of stream ecosystems across watersheds. In Republic of Korea, the Ministry of Environment has designated riparian zones to protect water quality and preserve aquatic ecosystems and continues to implement policies for their management. Given the long-term nature of riparian zone management, providing robust scientific evidence to justify and refine these policies is imperative. In this study, we quantitatively evaluated the role of riparian vegetation on water quality and aquatic ecosystems by using Bayesian Networks. Scenarios were designed to compare the individual effects of riparian vegetation and combined effects of urban and agricultural land use changes. The results indicated that riparian vegetation positively influenced water quality and the benthic macroinvertebrate index at the sub-watershed scale. When riparian vegetation and land use factors were jointly adjusted, scenarios with high riparian vegetation coverage showed improved probabilities of good BMI scores—24.3% under highly agricultural conditions and 27.4% under highly urbanized conditions—highlighting a substantial vegetation effect, particularly in urban areas. This study provides a scientific basis for guiding future riparian restoration and management efforts.
... Note: the terms freshwater and fresh water are interchangeable. [34]. About 420 million years ago, during the Silurian Period, ancient plants and arthropods began to occupy the land. ...
http://dspace.univ-relizane.dz/home/handle/123456789/685
... This can stress aquatic life and increase the growth of algae and bacteria. Higher temperatures in summer can lead to thermal stratification in lakes, where warmer surface water does not mix with cooler, deeper water, affecting oxygen distribution (Wetzel, 2001). Spring and fall seasons often have higher DO levels due to moderate temperatures and increased mixing of water layers (turnover in lakes). ...
The hematological parameters of Indian Major Carps (IMCs) such as Catla (Catla catla), Rohu (Labeo rohita) and Mrigal (Cirrhinus mrigala) are significantly affected by seasonal changes in environment. Seasonally escorted changes may influence their overall health, growth and survival. Environmental fluctuations such as temperature, dissolved oxygen (DO), nutrient levels, turbidity and sediment load affect hematological indices of IMCs. Vital parameters such as hemoglobin (Hb), hematocrit (Hct), red blood cell (RBC), white blood cell (WBC) counts, platelet count (PLT), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) are sensitive to seasonal stressors, and may be impacted with changes in surrounding environment. The important biomarkers such as alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), sodium hydroxide dismutase (SOD), catalase (CAT), lactate dehydrogenase (LDH) have been discussed in relation to the alterations induced by seasonal changes. Moreover, the review also explores effect of high temperature-induced thermal stress, photoperiod variations and hypoxia (low blood oxygen level) on the hematological profiles of IMCs. The influence of fish aging and seasonal erythropoiesis disparities are also taken into the consideration. Advance technological aspects such as integration of next-generation sequencing (NGS) and other modern technologies are being utilized to explore hematological analysis and disease diagnostics in aquaculture practices. This review article provides an overview of physiological adaptability of IMCs to seasonal changes and emphasizes on developing advanced monitoring methods to ensure their health and aquaculture sustainability.
... As expected, DO was inversely correlated with temperature, due, in part, to a lower DO saturation at higher temperature. Additionally, increased biological activity at warmer temperatures can increase the biochemical oxygen demand, which can also decrease DO (Wetzel 2001). Although there is no WQC for ammonia-N, nitrate-N, and nitrite-N, the values were generally below those that would cause toxicity, with some noted exceptions (Tomasso 1994;Tomasso and Grosell 2005). ...
The St. Johns River (SJR) is an ecologically and economically important estuarine river system undergoing extensive anthropogenic change. In this study, water quality parameters (dissolved oxygen, temperature, salinity, pH, hardness, alkalinity, ammonia–N, nitrate–N, and nitrite–N) and a suite of metals (cadmium, copper, lead, nickel, silver, and zinc) were measured in water samples collected from eight sites in the lower SJR from 2019 to 2022. This project was continued from previous work that documented these parameters in the river from 2017 to 2019. Aquatic communities such as phytoplankton can be indicative of river health; therefore, phytoplankton were also collected from each site, and the diatom component was identified. The total number of taxa in each sample ranged from 60 to 190, with 25 taxa accounting for the majority (64%). Similar to water quality, seasonal fluctuations in phytoplankton abundance and diversity were observed, with an increased relative abundance of Skeletonema costatum and Skeletonema subsalsum in times of lowered diversity. Furthermore, decreased phytoplankton diversity correlated with increased metal concentrations in the lower SJR. Multivariate analyses highlighted significant interactions among phytoplankton diversity and water quality variables. Significant parameters affecting phytoplankton biodiversity included salinity, pH, temperature, copper hazard quotient, and the nickel hazard quotient. This study provides new information about the impact of human disturbance on biotic communities and the complexity in predicting population changes.
... The composition and functioning of marine ecosystems and habitats are strongly dependent not just on the availability of light, but also the spectral composition of light penetrating the water column and reaching the sea floor (Markager and Sand-Jensen, 1992;Kirk, 1994). Light availability is the primary driver of photosynthesis and growth of phytoplankton and aquatic macrophyte vegetation, providing energy for all trophic levels in marine ecosystems (Kirk, 1994;Wetzel, 2001). In particular, the spectral distribution and intensity of light in the wavelength range 400-700 nm, called photosynthetically active radiation (PAR), is crucial for the photosynthesis of underwater primary producers (Kirk, 1994). ...
... The second sampling occurred in late summer, a period when groundwater and surface water levels typically reach their annual minimum and hydrological disconnection is most pronounced (Sophocleous, 2002). At this time of year, biogeochemical conditions such as reduced O 2 concentrations in bottom waters and elevated NH 3 and H 2 S levels tend to peak (Wetzel, 2001). Importantly, these parameters do not merely capture momentary conditions but rather integrate the cumulative effects of internal processes that have evolved throughout the preceding summer. ...
Between 2018 and 2023, central Europe experienced a series of droughts-one manifestation of climate change expected to increase in frequency in the future. These events increasingly expose aquatic ecosystems, such as floodplain water bodies, to hydrological extremes. Simultaneously, anthropogenic river modifications like channelization and diking have been progressively disconnecting semi-aquatic ecosystems from the main river. Here, we examined how drought and hydromorphological modifications affect the water quality of floodplain water bodies. Specifically, we investigated 36 floodplain water bodies near the Elbe River in Germany and analyzed water samples from spring and late summer 2022. We assessed connectivity (past frequency of surface connection to the stream) and effects of drought (evaporation measured by changes in stable water isotopes) using a scoring system. This system evaluated impairment and habitat loss, allowing us to quantify the impact of hydrological disconnection on floodplain water bodies. Severe impacts, including low surface oxygen (<3 mg/L), products of anaerobic decomposition, fish kills, and dry-outs, primarily affected water bodies with low connectivity (<10 %). Multiple linear regression linked low connectivity and high evaporation to habitat degradation (r 2 = 0.487, p < 0.001). Furthermore, dissolved oxygen concentrations increased with increasing chlorophyll a in connected lakes (p < 0.001), as expected, but no relationship was observed in disconnected lakes (p = 0.626). We attribute this lack of correlation to the decomposition of fine-grained organic sediments that have not been resuspended and flushed out in disconnected lakes. We conclude that river modifications for navigation reduce floodplain resilience to droughts, amplifying the effects of climate change on semi-aquatic ecosystems.
... As the interface between the upland terrestrial and lake ecosystems, the lakeshore riparian ecosystem plays a critical role in nutrient cycling and productivity. Additionally, the lakeshore littoral zone facilitates the transfer of resources, energy, and nutrients between the terrestrial and aquatic ecosystems (Naiman et al. 1998;Wetzel 2001;Gratton et al. 2008;Pusey and Arthington 2003). Given the number of important relationships between riparian and aquatic ecosystems, it is not surprising that spatial and temporal variation in adfluvial fish assemblage, composition, and characteristics have been linked to variation in riparian cover (Pusey and Arthington 2003). ...
Terrestrial invertebrates provide energy and nutrients to lacustrine systems. However, the extent to which lakeshore and riparian vegetation affects the diet of lake‐associated fish is not well known. We sampled six small lakes (< 1 km² surface area) on the West Coast of British Columbia, Canada, to determine if lakeshore riparian vegetation composition and extent affected the diet, feeding rate, and body condition of adfluvial cutthroat trout (Oncorhynchus clarkii clarkii). We found strong evidence that cutthroat sampled from a lake with an intact, old forest riparian had a different diet composition comprised largely of terrestrial invertebrates than cutthroat sampled from lakes with riparian forests representing a gradient of vegetation age and cover. We identified positive relationships between the intake of terrestrial invertebrates by cutthroat with the percentage of riparian vegetation overhanging and submerged along and decaying wood within the littoral zone. We also found positive relationships between the percentage of vegetation overhanging and submerged along the littoral zone and the percentage of overstory terrestrial vegetation. Our study contributes to a growing body of evidence recognizing the connections between upland terrestrial and lakeshore riparian and aquatic ecosystems.
... However, natural processes occurring in the reservoir do not always ensure the optimal metabolism of biogenic substances and stable utility parameters of eco-pools according to their primary function. Excessively high levels of biogenic substances result in water eutrophication, increase the rate of primary phytoplankton production (algal blooms), and can lead to the intoxication of the water reservoir, causing fundamental changes to water quality parameters [Wetzel 2001;Serafin et al., 2019]. The utility values of such a reservoir deteriorate, and using the water body can result in significant health problems for users [Walczak et al., 2023]. ...
... At all sample sites, except for VR, we observed the presence of filamentous algae. Filamentous algae develop in late summer [51] and are common in eutrophic rivers [52] that have long residence times [53], which is characteristic of the studied reservoirs. Troia et al. [49] report that in aquatic environments, an important factor determining invasiveness is nutrient availability, and invasion would increase with eutrophication. ...
Different communities of primary producers were surveyed in a series of five river reservoirs on the Sava River in southeast Slovenia. Seasonal differences of phytoplanktonic and phytobenthic communities were studied in the reservoirs of hydroelectric power plants. Macrophytes were surveyed in the summer, while phytoplankton and periphyton were sampled in the winter and summer of 2021. The taxonomic composition of diatoms was studied in greater detail and additionally analysed. The results showed that the species composition of phytoplankton and phytobenthos differed between seasons. The communities were also more similar between the seasons at the same sampling site than between the sampling sites. Temperature was the parameter that had the greatest impact on the taxonomic composition of phytoplanktonic and phytobenthic communities. In total, 51 algal taxa and 81 species of diatoms were recorded, respectively. Furthermore, 15 species of aquatic macrophytes were found. The abundance of phytoplankton was the highest in the lowest reservoir in the series, in Brežice, where the temperature was also the highest. The number of macrophytes also increased downstream, but their abundances were low, mainly due to coarse substrate on the banks consisting of rocks and boulders. Constructing additional reservoirs on this section of the Sava River could increase the probability of the substantial growth of phytoplankton and cyanobacteria within it. On the other hand, providing patches of finer substrates (gravel, pebbles) would support the abundance of macrophyte species, which could control the concentrations of nutrients in the summer and prevent the blooms more efficiently.
... Kedalaman maksimum danau laut di lokasi kajian memiliki nilai lebih dari 10 meter yang akan memungkinkan terjadinya stratifikasi suhu pada kolom air (Wetzel, 2001). Heiskary (1997) mengungkapkan bahwa dengan kedalaman lebih dari 10 meter, maka pertukaran massa air pada tubuh danau umumnya bersifat dimiktik, yaitu pertukaran yang berlangsung sebanyak dua kali yakni pada musim panas dan musim dingin. ...
Danau laut memiliki keunikan baik secara morfometri dan proses terbentuknya. Penelitian ini bertujuan menganalisis hidromorfologi danau laut di Kawasan Karst Mawasangka Timur, Kabupaten Buton Tengah, Sulawesi Tenggara. Analisis hidromorphologi meliputi L Max, B max, B mean, SI, orientasi danau laut, elevasi dan jarak dari pantai. Analisis hidromorfologi dilakukan dengan pengukuran langsung di lapangan, pengukuran dengan underwater drone, dan pengukuran melalui data citra penginderaan jauh dan peta sekunder. Danau laut yang dikaji meliputi Oe Mamba Kecil, Oe Mamba Besar, Pasi Bungi, Air Wali, dan Wa Piho Piho. Hasil perhitungan L max danau laut di area kajian berkisar 39-1.028 m, B max (30-685 m), B mean (21-487 m), SI (155,62-2.951 m 2), DI (0,381-0,425 m), Orientasi (NE-SW, N-S, dan E-W), elevasi (2-35 mdpal), jarak terhadap pantai (37-785 m) dan kedalaman maksimum (10-57,8 m). Nilai morfometri danau laut di Buton Tengah Sulawesi Tenggara memiliki rentang yang sama dengan danau laut tropis lain di Kalimantan, Marine lake has unique characteristics both in terms of morphometry and its formation processes. This research aims to analyze the hydromorphology of marine lakes in the East Mawasangka Karst Area, Central Buton Regency, Southeast Sulawesi. Hydromorphology analysis includes L Max, B max, B mean, SI, marine lake orientation, elevation and distance from shore line. Hydromorphology analysis was conducted by direct measurement in the field, measurement with underwater drones, and measurement through remote sensing image data and secondary maps. The lakes being studied are Oe Mamba Kecil, Oe Mamba Besar, Pasi Bungi, Air Wali, and Wa Piho Piho. The results of the calculations for L max marine lake in the study area range from 39 to 1,028 m, B max (30 to 685 m), B mean (21 to 487 m), SI (155.62 to 2,951 m²), DI (0.381 to 0.425 m), orientation (NE-SW, N-S, and E-W), elevation (2 to 35 m above sea level), distance from the coast (37 to 785 m), and maximum depth. (10-57,8 m). The morphometric values of the sea lake in Central Buton, Southeast Sulawesi, have a range similar to that of tropical marine lakes in Kalimantan, Papua, the Philippines, and Croatia.
... Moniewski (2015) vysvetľuje fenomén vzrastu pH intenzifikáciou procesu asimilácie v dôsledku vyššej teploty vody, kedy oxid uhličitý z vody vychytávajú fotosyntetické riasy. To súvisí aj so zvýšením koncentrácie O2 vo vode (Wetzel 2001), čo sme však v našom prípade nezaznamenali, keďže hodnoty O2 sú v sledovaných tokoch už 40 rokov relatívne stabilné. Klesajúci trend vykazuje BSK a približne od začiatku 21. storočia aj koncentrácia dusičnanového a amoniakálneho dusíka (DAD), zatiaľ čo EV od tohto obdobia stúpa. ...
The analysis of environmental changes in stream ecosystems from a temporal perspective is important for the assessment of athropogenic influences on them and it also has consequences for future management. The aim of this study is to demonstrate the long-term trends of selected physical and chemical characteristics of water in order to assess the impacts of different types of hydropower plants. The trends in the reference category (without upstream dis-continuity) show a continuous increase in water reaction while biochemical oxygen demand has decreased over the last 50 years. In the category of streams influenced by small hydropower plants, water reaction and dissolved oxygen concentration increased, while electrical conductivity has decreased over time. It is also evident that the development of the trend line in water reaction and conductivity was influenced by small hydropower plants. The trend lines of the category of streams influenced by large hydropower plants showed a steeper increase over time for water reaction, conductivity and dissolved oxygen. For each category, the trend lines representing the development of nutrient concentrations (ammonium-nitrogen, nitrate-nitrogen) have a para-bolic shape, as their concentrations peaked in the 1990s and started to decrease thereafter. However, statistical analyses are needed to assess the significance of the trends. As the long-term increase in water reaction is frequently observed in streams in Slovakia, more attention should be paid to this phenomenon in view of climate change and biodiversity protection.
... Central to this process is the role of dissolved oxygen (DO), which is the form of oxygen available for uptake by aquatic organisms. DO is essential for aerobic respiration, and its availability determines the health, distribution, and behavior of aquatic life (Wetzel, 2001). ...
Gas exchange is a vital physiological process in aquatic organisms, enabling the uptake of oxygen and the removal of carbon dioxide necessary for cellular respiration. Due to the lower concentration of dissolved oxygen in water compared to air, aquatic animals such as fish and shellfish have evolved specialized structures and mechanisms to optimize oxygen absorption. Fish possess highly developed
gill systems featuring counter-current exchange, while shellfish utilize gills or ctenidia adapted to their more sedentary lifestyles. The efficiency of gas exchange is influenced by environmental factors such as temperature, salinity, and dissolved oxygen levels, as well as physiological traits like respiratory surface area and metabolic rate. Adaptations to low-oxygen environments, including behavioral changes and the use of oxygen-binding pigments like hemocyanin, allow many species to survive in challenging conditions. Human-induced stressors, including pollution and eutrophication, further complicate gas exchange by damaging respiratory structures and depleting oxygen availability, threatening aquatic ecosystems.
... These two sections are separated by a thermal transition zone within which the temperature fluctuates greatly. The latter is known as the metalimnion [41][42][43]. ...
Abandoned mines represent an innovative and under-exploited resource to meet current energy challenges, particularly because of their geothermal potential. Flooded open-pits, such as those located in the Thetford Mines region (Eastern Canada), provide large, thermally stable water reservoirs, ideal for the use of geothermal cooling systems. Thermal short-circuiting that can impact the system performance affected by both free and forced convective heat transfer is hard to evaluate in these large water reservoirs subject to various heat sink and sources. Thus, this study’s objective was to evaluate the impact of natural heat transfer mechanisms on the performance of an open-loop geothermal system that could be installed in a flooded open-pit mine. Energy needs of an industrial plant using water from the flooded Carey Canadian mine were considered to develop a 3D numerical finite element model to evaluate the thermal impact associated with the operation of the system considering free and forced convection in the flooded open-pit, the natural flow of water into the pit, climatic variations at the surface and the terrestrial heat flux. The results indicate that the configuration of the proposed system meets the plant cooling needs over a period of 50 years and can provide a cooling power of approximately 2.3 MW. The simulations also demonstrated the importance of understanding the hydrological and hydrogeological systems impacting the performance of the geothermal operations expected in a flooded open-pit mine.
... The observed decrease in dissolved oxygen (DO) levels over time (Figure 7) correlates with the increase in temperature recorded in all treatments. This is consistent with the inverse relationship between temperature and DO solubility, where higher temperatures reduce the ability of water to retain oxygen [48]. Therefore, it is likely that the decrease in DO levels was primarily due to thermal effects, rather than the exclusive action of macrophyte systems. ...
The constant increase in industrialization and urbanization has led to the regular discharge of wastewater into the environment in excessive amounts, which has caused significant impacts on both human and wildlife ecosystems. The sustainable management and treatment of wastewater, whether of industrial or domestic origin, represents a crucial challenge in this century. In this study, phytoremediation was employed as a wastewater treatment strategy using two species of aquatic macrophytes: water hyacinth (Eichhornia crassipes) and duckweed (Lemna minor). The study was conducted over seven consecutive evaluation periods, with five-day intervals between each. The objective was to apply the multivariate HJ-Biplot methodology to evaluate the effects of phytoremediation of two species of aquatic microphytes on the physicochemical characteristics of wastewater from Milagro canton, Ecuador. Additionally, a microbiological analysis was conducted to determine the effectiveness of the floating macrophytes. The analysis was based on the measurement of various physicochemical parameters, such as pH, electrical conductivity (EC), dissolved oxygen (DO), oxidation–reduction potential (ORP), salinity, total dissolved solids (TDSs), biochemical oxygen demand (BOD), chemical oxygen demand (COD), hardness, and temperature. The results showed that the highest efficiency in pollutant removal was achieved with duckweed (Lemna minor) in five out of nine measured parameters, suggesting that this species was the most effective compared to the control sample and Eichhornia crassipes. The capacity of these macrophytes for wastewater treatment was confirmed by this study. To ensure effective water purification, timely extraction of aquatic macrophytes from water bodies is recommended. If this collection is not properly carried out, the nutrients absorbed and stored in the plant tissues may be released back into the aquatic environment due to plant decomposition.
... . Sie stellen einzigartige Habitate für Pflanzen, Invertebraten, Amphibien, Fische und Vögel bereit und sind Zonen des Austausches von organischem Material sowie Nährstoffen zwischen terrestrischen und pelagialen Lebensräumen (Strayer & Findlay 2010;Vadeboncoeur et al. 2011;Wensink 2016;Wetzel 2001). ...
... Measuring Chl-a is a cost-effective alternative to estimating phytoplankton abundance and biomass through cell counts [13], which require labourintensive laboratory analysis. Increasing Chl-a levels typically signal excessive algal growth and the potential of a harmful algal bloom [14]. The purpose of this study is to forecast the large-scale Chl-a concentration one week ahead in the Murray-Darling Basin for water management so that one can issue early warnings and implement timely interventions. ...
Reliable forecasts of large-scale chlorophyll-a (Chl-a) levels one week ahead in the Murray–Darling Basin are essential for water resources management, as increasing Chl-a levels in water bodies indicate possible harmful algal blooms, a serious threat for freshwater security. A lack of high-resolution data in space and time is a major constraint for delivering early warnings. To address data scarcity, we developed a forecasting model integrating remote sensing data and time-series modelling. Using in situ Chl-a measurements from Murray–Darling Basin water bodies, we locally recalibrated a two-band ratio algorithm, namely the Normalized Difference Chlorophyll Index (NDCI), from Sentinel-2 data to derive Chl-a levels. The recalibrated model significantly improved the accuracy of high Chl-a estimates in our dataset after mitigating data heteroscedasticity. Building on these improved satellite-derived Chl-a estimates, we developed a time-series model for forecasting weekly Chl-a levels including quantification of forecast uncertainty through prediction intervals. The developed model, validated at eight sites for 2021–2022 data, performed well at shorter lead times, showing R² = 0.41 and RMSE = 8.1 μg/L for overall performance at a one-week lead time. The prediction intervals generally aligned well with nominal levels, demonstrating their reliability. This study provides a valuable tool for the water managers/decision-makers to issue early warnings of algal blooms in the Murray–Darling Basin.
... Meanwhile, Talley et al. (2002) found that temperature is negatively related to fungal richness, but not abundance. Many authors documented that the aquatic fungal communities have been affected by temperature variations in temperate regions, as temperature could be control the metabolic rates of various species and the interplay between biotic and abiotic variables (Suberkropp 1992;Wetzel 2001;Bärlocher et al. 2008;Saad et al. 2014). ...
The aquatic environment has been contaminated by pyrethroids and triazole pesticide applications, which pose serious health risks to the aquatic ecosystem and human beings. Therefore, the current study aims to evaluate water quality parameters, fungal diversity, and distribution of snails and aquatic plants of certain Egyptian water courses contaminated with pyrethroids and triazole pesticides. Seasonal samples were taken throughout 2021 from different water courses at Giza Governorate and Tanta (Gharbeya Governorate). Qualitative and quantitative surveys showed significant differences in water physical parameters between the two investigated governorates. Deltamethrin, permethrin, Es-fenvalerate, and lambada-cyhalothrin showed the highest pyrethroids concentrations, while tebuconazole, tetraconazole, and difenoconazole were the highest triazole concentrations. Fungal diversity displayed 21 molecularly identified fungal species related to four fungal genera: Aspergillus, Fusarium, Penicillium, and Trichoderma. Penicillium sp. and Aspergillus niger were the most frequent species. Snail diversity recorded 10 and 9 species in Giza and Tanta, respectively. Physa acuta was the most abundant snail. Ten species of aquatic plants were observed in Giza, while six species were observed in Tanta. Specifically, Eichhornia crassipes and Lemna gibba were the dominant species in the two governorates, with the relative abundance (39 and 22%) in Giza and (27 and 23%) in Tanta, respectively. Water quality parameters and seasonal variations could control fungal diversity, snails, and aquatic plant distribution. Different relations between pesticides and biological communities may reflect the ability/inability of certain snails and fungi species to commensalism with pesticide concentrations. Continuous pesticide monitoring is essential for life below water and aligns with SDG14.
... Excessively low TH levels cause stress, hinder growth and make fish more susceptible to environmental fluctuations. It is seen that optimal TH conditions vary by species, but balanced hardness levels generally support the health and diversity of aquatic fauna (Wetzel 2001). ...
The study investigates the fish community structure and environmental drivers of Deepor Beel, a floodplain wetland situated in the Brahmaputra Valley of Assam, India. Recognized as a Ramsar site of international importance, Deepor Beel is a biodiverse habitat that supports a variety of flora and fauna, including a rich ichthyofaunal diversity. This research recorded 55 fish species across 9 orders and 21 families, with Cypriniformes and Cyprinidae being the dominant order and family, respectively. Seasonal variations were evident, with the monsoon season exhibiting the highest species richness due to the beel's connectivity with the Brahmaputra River. Environmental factors such as water temperature, pH, dissolved oxygen, turbidity and ammonia levels were identified as critical determinants of fish abundance and community structure. The study applied biodiversity indices like Shannon–Wiener, Margalef and Simpson indices to quantify species richness and evenness, highlighting significant diversity fluctuations across seasons. The monsoon and postmonsoon period recorded higher diversity and species richness compared to the winter and premonsoon period. The research also highlights the growing threats to Deepor Beel, including eutrophication, habitat degradation, pollution and the introduction of non‐native species. Despite these challenges, the beel remains an important ecological and economic resource, supporting fisheries and local livelihood. The findings underline the necessity for a sustainable management approach, including the implementation of conservation strategies to mitigate anthropogenic disturbances and preserve the ecological integrity of Deepor Beel. The study offers baseline data crucial for guiding future conservation efforts and emphasizes the need for formal management plans to ensure the long‐term sustainability of this vital wetland ecosystem.
... Additionally, plankton contribute significantly to the decomposition of organic matter and the bioremediation of water bodies by aiding in the natural purification of polluted waters and the breakdown of sewage. Their ability to assimilate and recycle nutrients is crucial in maintaining water quality and ensuring the sustainability of freshwater and marine ecosystems (Wetzel, 2001). Phytoplankton, in particular, are primary producers that drive aquatic food webs through photosynthesis, converting solar energy into organic matter. ...
... The pH of natural waters ranges from pH 2-12, depending on the buffering capacities of water bodies and dissolved organic matter; fluctuations in pH values can occur during periods of high primary productivity and acidification. 58 The phenomenon of pH homeostasis, which regulates differences in intracellular and extracellular pH, is primarily maintained by channeling cations like sodium (Na + ) and Ca 2+ through cell membranes and begins with the sorption of cations onto cell surfaces. 46,59 Sorption of NPls would block channel proteins, hindering pH homeostasis and resulting in more susceptibility to cell lysis. ...
Polystyrene nanoplastics altered the surface properties of cyanobacteria without affecting their growth or structure, highlighting their remarkable resilience and adaptive strategies in response to environmental challenges.
... Lebih rendahnya nilai DO di stasiun II diduga disebabkan oleh peningkatan suhu, di mana suhu tertinggi terdapat pada stasiun II. Hal ini didukung oleh pernyataan (Wetzel, 2001) bahwa oksigen dalam air berkurang ketika suhu meningkat. Kandungan oksigen terlarut akan mempengaruhi jumlah dan jenis makrozoobenthos di perairan (Widhiandari et al., 2021). ...
ABSTRAK Penelitian ini dilakukan untuk mengetahui kepadatan dan keanekaragaman makrozoobenthos, kondisi kualitas air berdasarkan parameter fisika dan kimia serta perbedaan kepadatan, keanekaragaman dan kondisi kualitas air antara stasiun di Danau Sabuah. Penelitian ini merupakan penelitian kuantitatif, pengambilan sampel dengan metode purposive sampling dimana lokasi penelitian dibagi menjadi 3 stasiun yakni inlet, pertengahan dan outlet. Pengambilan sampel makrozoobenthos dilakukan di 3 stasiun dimana setiap stasiun ditetapkan 3 titik pengambilan sampel selama 3 kali ulangan dengan interval waktu 7 hari. Pengukuran dan pengambilan sampel kualitas air meliputi suhu, kedalaman, kekeruhan, tipe sedimen, pH, DO dan amoniak dilakukan pada stasiun yang sama dengan stasiun pengambilan sampel makrozoobenthos. Berdasarkan hasil penelitian jenis makrozoobenthos yang ditemukan di Danau Sabuah sebanyak 8 spesies yang termasuk dalam filum Annelida, Uniramia dan Nematoda. Komposisi jenis makrozoobenthos yang paling banyak ditemukan dari filum Uniramia. Nilai kepadatan makrozoobenthos rata-rata berkisar antara 133 – 6.133 ind/m2. Nilai rata-rata indeks keanekaragaman makrozoobenthos pada masing-masing stasiun menunjukkan keanekaragaman jenis makrozoobenthos tergolong rendah. Kondisi parameter kualitas air pada lokasi penelitian menunjukkan nilai parameter suhu, pH, amoniak masih sesuai untuk kehidupan organisme akuatik. Sementara itu, nilai parameter DO menunjukkan nilai yang relatif rendah di semua stasiun. Hasil uji anova menunjukkan tidak ada perbedaan kepadatan dan keanekaragaman makrozoobenthos serta nilai suhu, kekeruhan, pH, DO dan amoniak antara stasiun. Sedangkan untuk parameter kedalaman menunjukkan adanya perbedaan nilai antara stasiun pengamatan. Kata kunci: Danau Sabuah, Makrozoobenthos, Parameter Fisika-Kimia ABSTRACT This study was conducted to determine the density and diversity of macrozoobenthos, water quality conditions based on physical and chemical parameters and differences in density, diversity and water quality conditions between stations in Sabuah Lake. This research is a quantitative study with purposive sampling method where the research location was divided into 3 stations namely inlet, middle and outlet. Macrozoobenthos sampling was carried out at 3 stations where each station was assigned 3 sampling points for 3 replicates with a time interval of 7 days. Measurement and sampling of water quality including temperature, depth, turbidity, sediment type, pH, DO and ammonia were carried out at the same station as the macrozoobenthos sampling station. Based on the results of the study of macrozoobenthos species found in Sabuah Lake as many as 8 species are included in the phylum Annelida, Uniramia and Nematoda. The composition of macrozoobenthos species most commonly found from the phylum Uniramia. The average macrozoobenthos density value ranged from 133 - 6,133 ind/m2. The average value of the macrozoobenthos diversity index at each station shows the diversity of macrozoobenthos species is low. The condition of water quality parameters at the study site shows the value of temperature, pH and ammonia parameters are still suitable for the life of aquatic organisms. Meanwhile, the value of the DO parameter shows a relatively low value at all stations. The ANOVA test showed no difference in macrozoobenthos density and diversity, and temperature, turbidity, pH, DO and ammonia between stations. While the depth showed a difference in values between stations. Keywords: Lake Sabuah, Macrozoobenthos, Physical-Chemical Parameter.
The Pampa plain is located in the central part of Argentina. This region shows heterogeneity in its soils and climate, and has been subjected to high anthropic pressure, being dominated by agriculture and cattle breeding. It hosts thousands of permanent shallow lakes that are characterized as polymictic, naturally eutrophic or hypereutrophic, and slightly alkaline. Currently, most of them are in a phytoplankton-turbid regime with a high abundance of phytoplankton. Some lakes remain in a vegetated-clear regime, dominated by submerged macrophytes, and others are in an inorganic-turbid regime with high concentrations of inorganic suspended solids. Factors acting at different scales (local, landscape and regional) interact resulting in the current characteristics of these shallow lakes. We found that the key drivers of phytoplankton chlorophyll a concentration (Chla) in these aquatic systems are total nitrogen (TN) and the percentage of crops in their surrounding area. Management strategies to avoid or diminish the development of anthropic activities—in particular agriculture—in the nearby zones of the lakes should be established to mitigate the deterioration of these shallow lakes.
Numerous shallow lakes are present in the Argentine Pampa plain. In the Southern Pampa plain most are freshwater or subsaline lakes, whereas in the Northern and Western Pampa plain lakes range from subsalines to hypersalines, with higher TDS concentration during the wet season, when water balance is usually negative, than in the dry season. Pampean lakes are mostly alkaline, without significant regional or seasonal pH variations. The waters of most Southern Pampean lakes are bicarbonate-sodium-type, whereas Northern Pampean lakes range from bicarbonate-sodium-type to chloride-sodium-type. Western Pampean lakes exhibit the widest compositional range. Weathering and evaporation-precipitation processes mainly control the water chemistry. Most of them are oversaturated in Ca and Mg-carbonates, theoretically evolving from calcite composition towards the precipitation of Na-carbonates, with halite as the final precipitate. Monovalent ions (Cl−, K+, and Na+) are mainly present as free aqueous ions, whereas HCO3− is the most abundant carbon species. Other elements (S, Ca, and Mg) tend to form complexes. The stable isotopic compositions also evidence evaporation processes, more intense during the wet season (austral summer). Groundwater-surface water interactions in several Northern and Western Pampean lakes, modelled using environmental tracers (i.e., δ18O and 222Rn), indicate groundwater discharge occurring at different scales.
Utah Lake continues to be a highly abused ecosystem ever since Americans of European decent settled along its shores over 150 years ago. The lake has lost its ecological integrity and is in poor health by most qualitative and bioassessment based standards. Its resilience to future perturbation and resistance to improvement (restoration) appears to be compromised.
There is much concern as to the future of Utah Lake and what can be done to improve its condition (i.e., health, integrity), including the reduction of algal blooms and restoration of its native biota. However, there has been little to no effort expended to examine or understand the importance of the lake’s food web and how top-down, trophic cascades effect and respond to current conditions or how biomanipulation may help restore its ecosystem health despite decades of research documenting their importance worldwide. Restoring the lake cannot proceed without this understanding. Consequently, a representative food web model was urgently needed.
This report presents the first ever proof-of-concept, trophic- level, mass- balanced foodweb model of Utah Lake that will allow researchers and managers to understand and better manage this important ecosystem. The model chosen and developed was the widely used and freely available EcoPath with EcoSim (EwE) model.
Biomasses, diets, and production/biomass ratios of eighty- one taxonomic groups were modeled as inputs including taxa from phytoplankton, zooplankton, benthic invertebrates, fishes, benthic algae, and detritus based on lengthy synthesis of extremely limited data augmented with literature values. Carp removal program fisheries ‘catch’, and chironomid export estimates were also modeled.
The EwE model produced dozens of ecosystem metrics and indices, most of which supported the premise that Utah Lake ecosystem is impaired and dominated by only a handful of taxa including invasive Common Carp, other invasive fishes, and pollution tolerant chironomids, and that the lake energy sources are co-dominated by water column primary production and strongly respiring detritus mostly in the form of detrital snow. Model results also showed that the lake has low robustness (e.g., resistance), is well below optimal trophic functioning, and is in an ‘immature’ early succession stage primarily because of chronic wave action that consistently disturb unconsolidated sediments and reset the food web thus preventing maturation of the system and because of eutrophication that keeps the lake in a younger or ‘bloom’ state.
The carp reduction program had both negative and positive mixed level trophic impacts on several groups. These results support continued and increased carp reduction efforts.
The EwE model clearly demonstrated that increased monitoring and research are essential to best manage the lake. Additional model inputs, forcing functions, scenarios, and incorporation with models being developed by others are required to ensure that the EwE model is the most useful tool for scientifically managing Utah Lake and is the go-to model. This proof-of-concept draft Utah Lake EwE model is available to all interested researchers and managers. Collaboration, refinement, and utilization by others is strongly encouraged.
Buku ini menyajikan pembahasan menyeluruh tentang
kimia lingkungan, yang sangat relevan bagi akademisi dan
praktisi. Isi buku dimulai dengan pengenalan konsep dasar
kimia lingkungan dan berbagai jenis pencemaran, termasuk
pencemaran udara, air, dan tanah. Pembahasan ini
mencakup definisi, siklus pencemaran, serta berbagai
contoh nyata pencemaran yang terjadi di lingkungan sekitar
kita.
Bagian tentang kimia tanah menjelaskan detail unsur hara
makro dan mikro yang penting untuk kesuburan tanah,
serta peran bahan organik dan anorganik dalam menjaga
keseimbangan kimia tanah. Siklus nitrogen dan fosfor, yang
merupakan komponen kunci dalam nutrisi tanaman, juga
diuraikan dengan jelas. Buku ini juga membahas reaksi
pertukaran kation dan kapasitas tukar kation (CEC), serta
pentingnya pengukuran dan pengendalian keasaman tanah.
Pada bagian kimia air, buku ini menjelaskan peran vital air
dalam kehidupan, sumber-sumber air sehari-hari, serta
perbedaan antara air tanah dan air permukaan. Sifat-sifat
unik air, baik dalam bentuk padat maupun cair, dibahas
secara rinci. Selain itu, buku ini juga mengulas tentang
pengaruh mikroorganisme terhadap kimia air, siklus
hidrologi, dan berbagai bahan kimia yang ada dalam
perairan, seperti oksigen, karbon dioksida, dan silikon.
Buku ini juga mengkaji pencemaran udara, air, dan tanah
secara mendalam, termasuk dampaknya terhadap
kesehatan dan lingkungan. Pembahasan mencakup
langkah-langkah pencegahan dan pengendalian
pencemaran yang dapat diimplementasikan. Akhirnya,
buku ini membahas pemanasan global, penyebab
utamanya, serta dampak signifikan yang ditimbulkannya
terhadap bumi. Buku ini merupakan sumber daya yang
berharga bagi siapa pun yang ingin memahami lebih dalam
tentang interaksi kimia di lingkungan dan mencari solusi
praktis untuk mengatasi masalah pencemaran.
In August 2015-2018, the phytoplankton of 15 reservoirs of the Volga, Kama, Don rivers; the Volga-Don Canal; and the unregulated part of the Lower Volga was studied. A decrease in the species richness , diversity, cell size, total phytoplankton, and phytoflagellate biomass in the Volga-Kama cascade is observed from the upper to the lower reaches of the regulated rivers. This reflects the zonation and hydrological continuity. The proportion of biomass of nonheterocystous cyanobacteria in the reservoirs increases with increasing salinity of their waters. The trophic state of the reservoirs is assessed based on the phytoplankton biomass value.
Aquatic ecosystems regulate and play great ecological roles, for instance, provide habitats for flora and fauna, nutrient cycles, maintain stream flow, climatic control, and support livelihood security through fisheries, recreational activity etc. However, anthropogenic activities have dramatically deteriorated the aquatic ecosystem. Geospatial techniques are significant for the extraction of morphometric features of lake. An analysis of 97 years (from 1922 toposheets to Google Earth Images, 2019) of Chilua Lake in Tarai region , revealed deterioration scenario. The extent of Chilua Lake is reduced up 27.75% in 97 years from 1922 to 2019. As per the 500 m buffer analysis surrounds of lake Chilua, 1.3% built-up area increased around the lake within 15 years (from 2004 to 2019). For 6 to 8 months, the lake goes dry out and the water left behind in patches and engaged in various activities by the locals. Lake bed is covered by stream like storage (20%) and water is available during all seasons, water left in patches during dry season (15%), littoral plant coverage (45%), farming (11%), dry lake bed (10%), and built-up area (0.3%). Increasing built-up, farming on dry bed, dumping of solid waste and sewage entry have contributed directly pushed towards eutrophic status lake ecology at C1 (sewage entering sources) and C3 (agricultural practices) based on the BOD, BO, TP, NO 3 , SD, GPP, Chla, etc. This study investigates factors of lake deterioration and suggest the practices of Stewardship in the way of basin lake management techniques (BLMT) and Tripple-P model.
We experimentally demonstrate that organic matter from open-ocean fish farms, when deposited onto aphotic cohesive sediments, can significantly alter microbial nitrogen cycling. Initially, sediments act as sites of fixed-nitrogen removal via efficient nitrification−denitrification coupling. However, with continued organic loading, they shift to retaining fixed nitrogen and exporting ammonium. In lab-based sediment microcosms, we measured sediment−seawater fluxes of nitrate + nitrite (NO x), ammonium (NH 4 +), and dinitrogen (N 2) following short-term additions (1 and 7 days) of fresh fish waste across moderate (1.1− 3.2 g C m −2 d −1) to heavy (11.2 g C m −2 d −1) loading scenarios. After 1 day, NH 4 + was efficiently converted to N 2. After 7 days, however, organic carbon accumulated and NH 4 + export dominated. 16S rRNA gene sequencing revealed that this shift in function was linked to reduced nitrification efficiency, increased dissimilatory nitrate reduction to ammonium (DNRA), and potential stimulation of nitrogen fixation. Our findings suggest that sustained organic enrichment from open-ocean aquaculture can disrupt benthic nitrogen removal processes and promote fixed-nitrogen retention with potential consequences for coastal nutrient dynamics. These results have important implications for the ecological sustainability of offshore aquaculture and can inform ecosystem-based management strategies.
Inland waters (lakes, reservoirs, and rivers) serve as important regulators of global climate change and carbon (C) cycling. China's inland water systems significantly regulate regional C budgets. However, our understanding of the long-term spatiotemporal patterns and underlying mechanisms of dissolved carbon (DC) storages and fluxes in inland waters remains limited. This study examined lake and reservoir DC storage and river DC flux, quantifying their changes in China over the past three decades. We found that inland water DC stocks in China increased from 96 Tg C in the 1990s to 142 Tg C in the 2010s while DC river flux did not significantly change (13.2 ± 0.4 Tg C/yr). Findings also showed that a combination of climate change, anthropogenic disturbance, and water chemistry collectively drove inland water DC dynamics. River DC was more directly driven by climate and anthropogenic factors (>50%) while lakes and reservoirs were more directly influenced by water chemistry (>70%). Additionally, climate factors can explain changes in dissolved inorganic carbon (DIC) concentrations via water chemistry factors (i.e., electrical conductivity (EC) and pH), while, collectively, climate and the nutrient status can typically explain changes in DOC concentrations. This study emphasizes the important role that inland water plays in the global C balance and underscores the necessity of considering it in future C budgets.
This study presents a bioassessment of lowland streams in the Shivalik Himalayas, utilizing benthic macroinvertebrates as bioindicators to evaluate the ecological health of the streams. Lowland streams of Shivalik Himalayas were assessed to analyze the diversity and distribution of macroinvertebrate communities in relation to various physicochemical parameters and anthropogenic influences. The results revealed significant variations in water quality across the sites, with key parameters such as pH, dissolved oxygen, conductivity, and nutrient levels influencing the assemblage patterns of macroinvertebrates. The water quality at different locations based on macro-invertebrate available taxa has also been validated using WAWQI (Weighted Arithmetic Water Quality Index). The study identified 25 families of benthic macroinvertebrates, encompassing 11 taxonomic groups, with notable variations in abundance and diversity among sites. Three biotic indices—BMWP/ASPT (Biological Monitoring Working Party/Average Score Per Taxon), FBI (Family Biotic Index), and HKHBIOS (Hindu Kush Himalayan Biotic Score) were used to evaluate the water quality, showing moderate to good ecological conditions at less disturbed sites and indicating pollution and degradation at sites with higher anthropogenic activities. Statistical analysis by using ANOVA showed significant differences among the biotic indices applied. The findings highlight the utility of benthic macroinvertebrates as reliable bioindicators for assessing stream health and underscore the need for integrated management strategies to mitigate anthropogenic impacts on freshwater ecosystems in the Himalayan region.
This chapter explores the essential role of water in regulating Earth’s environmental systems. This chapter provides an in-depth examination of the hydrosphere, which encompasses all forms of water on Earth, including oceans, rivers, glaciers, and atmospheric water vapor. It highlights the critical functions of the hydrological cycle in maintaining water balance and sustaining life. Furthermore, this chapter discusses the significance of ocean waters, their temperatures, salinity, and the role of ocean circulation in climate regulation. Special attention is given to current challenges facing the oceans, including the impact of climate change, pollution, and overfishing. The dynamics of water’s role in Earth’s climate, ecosystems, and human societies are analyzed, emphasizing the need for sustainable water management and environmental protection.
A systematic classification of lakes is essential for effective management, conservation, and scientific research. However, existing approaches often overlook the continuous variability of certain indicators among lakes and are constrained by data availability. In this study, we developed a classification system for 439 lakes larger than 10 km2 in China using geomorphological, hydrological, climatic, and landscape features, employing an archetypal analysis approach. Based on the model fitting results, we identified six distinct lake archetypes, which differ from the traditional five classifications based on geographical regions in China. The water quality of lakes across different archetypes responded to a range of geographic, hydrological, meteorological, soil, and anthropogenic factors. Lakes with the highest nutrient levels were predominantly found in Archetypes 5 and 6, located in northeastern China and the Yunnan-Guizhou Plateau, respectively, followed by Archetype 3. In these regions, nutrient levels were strongly associated with human activities. In contrast, indicators such as conductivity and permanganate index in different archetypes were primarily influenced by non-human activities, with the impact of human activities being relatively weak. Phytoplankton, represented by chlorophyll-a, showed a significant response to total phosphorus only in Archetypes 3 and 6, while the response to nitrogen and phosphorus was not significant in the other archetypes. This variation in phytoplankton responses may have been influenced by the climatic conditions in these regions, such as temperature. These findings underscore the importance of developing targeted management and conservation strategies for different lake types, considering their distinct responses to nutrient and temperature changes. Smaller lakes, with relatively simple ecological characteristics, can be managed through targeted strategies tailored to specific types. In contrast, larger lakes require more specialized conservation and management efforts to tackle their complex ecosystem challenges.
The Canadian Prairie Pothole Region is a notable hotspot for cyanobacteria-dominated lakes. This study found minor variations in cyanobacterial genera across these lakes yet observed significant differences in standing biomass, as the lakes ranged from oligotrophic to hypereutrophic classifications. A correlational analysis of nutrients, specifically total phosphorus (TP) and total nitrogen (TN) revealed that the limiting nutrients varied considerably across the region. Of the lakes studied, cyanobacterial biomass was P-limited in 21 lakes, N-limited in 3 lakes, and co-limited by both P and N in 23 lakes. Surprisingly, in 32 lakes, the biomass was limited by neither P nor N. In these lakes, iron (Fe) emerged as the most likely limiting nutrient, given a relatively narrow range of free ferric Fe (pFe) between 18 and 26. Cyanobacteria can create biomass under Fe stress by producing Fe-scavenging siderophores that target pFe. However, in neither P- nor N-limited lakes, there was a lack of correlation between siderophore concentrations and cyanobacterial biomass (r = 0.05), indicating that the siderophores were unable to scavenge Fe and thereby utilize the available P and N to produce further cyanobacterial biomass. Our findings suggest that these Fe-starved eutrophic lakes exhibited a paradox of slow-growing yet high cyanobacterial biomass, challenging the notion that only oligotrophic lakes embody slow-growing metabolisms. Overall, our study highlights the importance of considering nutrient limitations on cyanobacterial growth and incorporating macro- (P and N) and micro- (Fe) nutrient limitation considerations into existing nutrient management strategies to mitigate cyanobacterial dominance effectively.
Supplementary Information
The online version contains supplementary material available at 10.1007/s10533-025-01234-7.
Статтю присвячено комплексному дослідженню ресурсів озер Ковельського адміністративного району Волинської області України та перспектив їх використання в рекреаційній діяльності. Проведено аналіз найважливіших гідрологічних та морфометричних характеристик озер, які є визначальними для розвитку туризму та рекреації в розрізі об’єднаних територіальних громад та басейнів найголовніших річок.Установлено, що в районі зосереджено значні природні ресурси озер (загальна площа водного дзеркала становить 10 941,85 га, об’єм водної маси сягає 457 907,1 тис. м3). На дослідженій території наявні значні запаси озерних відкладів (сапропелів), які можуть використовуватись у різних галузях господарства. Сапропелеві ресурси становлять 46,9 млн т і представлені карбонатним (22 938,6 тис. т), залізистими (11 391,5 тис. т), органо-силікатним (7329,4 тис. т), органічним (4839,3 тис. т) та кремнистим (470,5 тис. т) класами. Перспективними для бальнеологічного використання є сапропелі органічного та органо-силікатного класів (12 168,7 тис. т). Природні ресурси озер можуть широко використовуватись у різних галузях економіки, сільського господарства та рекреаційно-туристичній діяльності (водні види спорту, рибальство, пляжний відпочинок, бальнеологія та ін.).
This study reveals seasonal and spatial patterns of chlorophyll-a dynamics shaped by nutrient loading and water temperature.
Understanding the geomorphology of lake basins is essential for various scientific disciplines, including limnology (the study of inland waters), geology, and environmental science. It provides insights into the history, processes, and environmental conditions that shape lakes and contributes to our understanding of the dynamic interactions between geology, climate, and hydrology in lake ecosystems. The interaction between lakes and groundwater can pose several challenges, often intertwining hydrological, ecological, and socioeconomic issues.
Laguna de Bay, the largest lake in the Philippines and third in Southeast Asia, is constantly challenged by anthropogenic activities. Hydrochemistry was investigated to understand its spatial and seasonal dynamics in terms of anthropogenic and natural influences. Water sampling campaigns were done during dry and wet seasons from the western, southern, and eastern parts of the bay representing residential and industrial areas, agricultural and residential areas, and agricultural area in the catchment, respectively. Sites include crucial waterbody spots such as important tributaries, i.e., rivers and lakeshores. Major ions, Cl−, Na+, Ca2+, Mg2+, K+, and NO3−, were analyzed. Using Canonical Correspondence Analysis (CCA) and ion molar ratios assessments, water origin was traced using the major ions, land cover, and geological characteristics. In general, results showed that in terms of concentration the dominance of the ions is as follows: Cl− > Na+ > Ca2+ > Mg2+ > K+ > NO3− whether wet or dry season. However, this varies when looking at the individual river. In terms of the total ion concentrations at each site, the highest contributors were the tributaries in the western part and the lakeshore in the southern part. In general, all the measured major ions are influenced by the anthropogenic origins mainly by built-up at the same time geogenic sources were identified, Cl−, Ca2+, Mg2+ are inclined to the Pliocene Quaternary volcanic area whereas Cl−, K+ and Na+ are associated from seawater discharges. In terms of tendencies, south and east bays showed vulnerability to both anthropogenic and magmatic influences. West bay showed the dominance of anthropogenic influence. The results presented the geogenic and anthropogenic origins of Laguna de Bay’s hydrochemistry that can help in coming up with better management programs to improve the water quality.
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