Lakes Of Different Trophic Status Research Articles

Temporal and spatial distribution of macrozoobenthos in three lakes of different trophic states: a case study of the Narochianskie lakes (Belarus)

Temporal and spatial distribution of macrozoobenthos in three lakes of different trophic states: a case study of the Narochianskie lakes (Belarus)

Characteristics of the Low Molecular Weight Metabolome of Potamogeton Natans L. (Potamogetonaceae) from Lakes of Different Trophic State (Karelian Isthmus, Northwest Russia)

The qualitative and quantitative component composition of low molecular weight volatile organic compounds (VOCs) of the essential oil of the floating-leaf pondweed (Potamogeton natans L., Potamogetonaceae family) growing in various lakes of the Karelian Isthmus (North-West of the Russian Federation) in the fruiting stage was investigated in detail for the first time by gas chromatography-mass spectrometry. The low molecular weight metabolome (LMWM) of P. natans contained 138 components, 128 of which were identified. VOCs belonging to esters, alcohols, and various functional groups dominated the LMWM of floating leaf pondweed from mesotrophic and eutrophic lakes. A significant similarity was found between the component composition of VOCs of floating leaf pondweed from mesotrophic and eutrophic lakes. Many of the substances found in the LMWM of P. natans can be attributed to biologically active compounds. This opens up prospects for the use of this plant (particularly manool and ecdysteroids from its LMWM) for various economic applications as a valuable natural raw material. Due to the characteristic of the floating leaf pondweed's substantial resistance of its LMWM to the factor of the trophic status of the lakes, it is feasible to use it as an ecological indicator of significant disruptions in aquatic environments.

Changes in native fish communities in response to the presence of alien brown bullhead (Ameiurus nebulosus) in four lakes (Poland)

The aim of the study was to determine changes in the abundance of Ameiurus nebulosus and native fish in four lakes after 4–7 years. It was hypothesised that A. nebulosus would be the dominant species of fish in various types of lakes. The study was conducted in the summer of 2014 and 2018–2021, using Nordic multi-mesh gillnets. We indicated that relative numbers and biomass of A. nebulosus decreased in the oligo-mesotrophic lake, while increased in lakes of higher trophic conditions. Body weight and total length of A. nebulosus fluctuated from 3.2 to 283.3 g and 64 to 267 mm, respectively. The coefficient of condition of this species varied widely from 0.2 to 1.8 with the highest and lowest values in the meso-eutrophic lake. Ameiurus nebulosus accounted for 0.2–34.1% of the total numbers and 2.4–36.5% of the total biomass of the fish community. In the mesotrophic and meso-eutrophic lakes, A. nebulosus was a dominant component of the fish community after 7 years. The percentage contribution of A. nebulosus to the total numbers of fish decreased with the increasing trophic status of the studied lakes. Our study showed that A. nebulosus could be one of the factors responsible for a decrease in the number of native fish species and a change in the taxonomic structure of native fish in lakes of different trophic status (from oligo-mesotrophy to eutrophy).

Microbial communities, resistance genes, and resistome risks in urban lakes of different trophic states: Internal links and external influences

Anthropogenic discharge of nutrients, metals, and antibiotics poses multiple threats to the health of aquatic ecosystems and humans, e.g., causing eutrophication, and introduction of resistance genes into human pathogens. The potential link between microbial communities, resistance genes, and eutrophication levels in urban lakes is complex and remains unclear, which is crucial for ecological and human health risk assessment. Here, five urban lakes of different trophic conditions were investigated to quantify their microbial diversity, and high-resolution profiles of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) were established. Metagenome and multivariance analyses indicated that the microbial structures, distribution of resistance genes and mobile genetic elements (MGEs), and virulence factor genes (VFGs) significantly differed between the lakes. The hypereutrophic lake Nanhu harbored the lowest microbial diversity but the highest level of resistance genes. Microbial communities and MGEs were identified as the main drivers in shaping the profiles of ARGs and MRGs, while external environmental factors played an indirect role in the changing resistance genes. Two members of Proteobacteria, Aestuariivirga and Limnohabitans were identified as predominant bacterial hosts of ARGs in most samples. In addition, the resistome risk scores were found positively correlated with water quality factors and negatively correlated with microbial diversity in the urban lakes. Our study provides novel insights into the link between microbial diversity, MGEs, and the potential dissemination risk of ARGs in urban lakes.

Relief of Phosphate Limitation Stimulates Methane Oxidation

Aquatic ecosystems such as shallow lakes and wetlands are important emitters of the greenhouse gas methane (CH4). Increased phosphorus (P) loading is expected to increase CH4production in these ecosystems. This increased CH4production can potentially be mitigated by increased CH4oxidation, but how P availability affects methane-oxidizing bacterial (MOB) community composition and potential CH4oxidation remains to be tested. Here, we incubated MOB from sediments of four subtropical lakes of different trophic states for 7 days at different phosphate (PO43-) concentrations to determine the effects of P on MOB community composition and potential CH4oxidation. We measured CH4consumption daily and compared CH4oxidation during the exponential growth phase. Furthermore, we determined MOB community composition at the end of the incubations using qPCR of thepmoAgene. To test for differences in N and P uptake, we determined bacterial biomass N and P content. We found that increases in PO43-concentrations until 10 µM significantly increased CH4oxidation. PO43-also increased bacterial biomass P content, while N content was not affected. MOB community composition was not affected by PO43-but more strongly correlated to lake of origin, likely due to the short duration of the incubations. Our results show that PO43-can not only stimulate CH4oxidation indirectly through increased CH4production, but also directly by increasing MOB growth. Importantly, these effects only occur at low PO43-concentrations, indicating that at high nutrient loads the increased CH4oxidation will likely not mitigate the increased CH4production.

Comparing microscopy and DNA metabarcoding techniques for identifying cyanobacteria assemblages across hundreds of lakes

Accurately identifying the species present in an ecosystem is vital to lake managers and successful bioassessment programs. This is particularly important when monitoring cyanobacteria, as numerous taxa produce toxins and can have major negative impacts on aquatic ecosystems. Increasingly, DNA-based techniques such as metabarcoding are being used for measuring aquatic biodiversity, as they could accelerate processing time, decrease costs and reduce some of the biases associated with traditional light microscopy. Despite the continuing use of traditional microscopy and the growing use of DNA metabarcoding to identify cyanobacteria assemblages, methodological comparisons between the two approaches have rarely been reported from a wide suite of lake types. Here, we compare planktonic cyanobacteria assemblages generated by inverted light microscopy and DNA metabarcoding from a 379-lake dataset spanning a longitudinal and trophic gradient. We found moderate levels of congruence between methods at the broadest taxonomic levels (i.e., Order, RV=0.40, p < 0.0001). This comparison revealed distinct cyanobacteria communities from lakes of different trophic states, with Microcystis, Aphanizomenon and Dolichospermum dominating with both methods in eutrophic and hypereutrophic sites. This finding supports the use of either method when monitoring eutrophication in lake surface waters. The biggest difference between the two methods was the detection of picocyanobacteria, which are typically underestimated by light microscopy. This reveals that the communities generated by each method currently are complementary as opposed to identical and promotes a combined-method strategy when monitoring a range of trophic systems. For example, microscopy can provide measures of cyanobacteria biomass, which are critical data in managing lakes. Going forward, we believe that molecular genetic methods will be increasingly adopted as reference databases are routinely updated with more representative sequences and will improve as cyanobacteria taxonomy is resolved with the increase in available genetic information.

On the parameterization of phytoplankton primary production in water ecosystem models

Parametrization of the formation of organic matter in ecological models is traditionally carried out by using the dependence of the Michaelis – Menten – Monod type [Monod, 1942], which describes the growth rate of algal biomass depending on the factor limiting their development. One of the biggest drawbacks of these dependences is the presence of empirical parameters in them, which in a complex way depend on environmental factors and are an individual characteristic of various types of algae. These parameters in the models actually become fitting coefficients that provide the best fit between observational data and modeling results, which does not allow for effective diagnostics and forecasting of the state of aquatic ecosystems. In this work, on the basis of dimensional analysis, a parametrization was obtained that describes the photosynthesis of algae depending on the parameters relatively easily measured in natural conditions - total solar radiation, phytoplankton biomass, and water transparency. Parametrization has been verified according to observations on more than 30 different types of lakes located in different regions of the world. The calculated data are in satisfactory agreement with the data of field observations, both qualitatively and quantitatively. Discrepancies in field and calculated data may be due to the fact that the species composition of algae in lakes of different trophic status is not taken into account, which can lead to errors in assessing the efficiency of using solar radiation. Discrepancies may also be related to the total solar radiation, rather than photosynthetic active radiation, which varies in different geographic and atmospheric conditions. The proposed parametrization can be used in the development of mathematical models of lake ecosystems, as well as to determine the trophic status of poorly studied water bodies.

Seasonal dynamics of zooplankton in lakes of different trophic status

In the article, we present the data about the dominant complexes of zooplankton species in the pelagic zone of lakes Naroch, Myastro, Batorino (2014 –2019), Malye and Bolshie Shvakshty (2014 –2015), Svir (2018). The seasonal dynamics of zooplankton is analysed. The contribution of taxonomic groups and individual species in the abundance and biomass of zooplankton in lakes with different trophic status is studied. We noted two peaks in the seasonal dynamics of zooplankton. Rotifers prevailed in the spring, while Crustacea dominated in the summer-autumn period. The relative biomass of cladocerans increased and the proportion of copepods decreased with the increasing of trophic status of the lakes.

Nonlinear pattern and algal dual-impact in N2O emission with increasing trophic levels in shallow lakes

Shallow lakes are considered important contributors to emissions of nitrous oxide (N2O), a powerful greenhouse gas, in aquatic ecosystems. There is a large degree of uncertainty regarding the relationship between N2O emissions and the progress of lake eutrophication, and the mechanisms underlying N2O emissions are poorly understood. Here, N2O emission fluxes and environmental variables in different lakes along a trophic state gradient in the Yangtze River basin were studied. N2O emission fluxes were –1.0–53.0 μg m–2 h–1 and 0.4–102.9 μg m–2 h–1 in summer and winter, respectively, indicating that there was marked variation in N2O emissions among lakes of different trophic state. The non-linear exponential model explained differences in N2O emission fluxes by the degree of eutrophication (p < 0.01). TN and chl-a both predicted 86% of the N2O emission fluxes in shallow lakes. The predicted N2O emission fluxes based on the IPCC EF5r overestimated the observed fluxes, particularly those in hyper-eutrophic lakes. These findings demonstrated that nutrient-rich conditions and algal accumulation are key factors determining N2O emission fluxes in shallow lakes. Furthermore, this study also revealed that temperature and algae accumulation-decomposition determine an N2O emission flux in an intricate manner. A low temperature, i.e., winter, limits algae growth and low oxygen consumption for algae decomposition. The environment leaves a high dissolved oxygen concentration, slowing down N2O consumption as the final step of denitrification. In summer, with the oxygen consumed by excess algal decomposition, the N2O production is limited by the complete denitrification as well as the limited substrate supply of nitrate by nitrification in hypoxic or anoxic conditions. Such cascading events explained the higher N2O emission fluxes from shallow lakes in winter compared with summer. This trend was amplified in hyper-eutrophic shallow lakes after algal disappearance. Collectively, algal accumulation played a dual role in stimulating and impeding N2O emissions, especially in hyper-eutrophic lakes. This study expands our knowledge of N2O emissions from shallow lakes in which eutrophication is underway.

Atlas of picocyanobacteria monoclonal strains from the collection of CNR-IRSA, Italy

This atlas aims to provide an overview of the picocyanobacteria cultures hold by the CNR-IRSA collection. These are monoclonal strains mostly of the genera Synechococcus and Cyanobium. These strains were mainly isolated from lakes of different trophic status around the globe and, so far, they are not available in other collections of algae and (pico)cyanobacteria. Here we summarise the main characteristics of these strains, including some previously published data, and offer most of the strains as material available for research to every scientists upon request.

Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data

Freshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. In the eutrophic Lake Baldegg and the oligotrophic Lake Sarnen, we specifically examined seasonal sediment porewater chemistry, organic matter sedimentation rates, as well as 33-year of historic water column data. We find that the eutrophic Lake Baldegg, which contributed to the removal of 20 ± 6.6 gN m−2 year−1, effectively removed two-thirds of the total areal N load. In stark contrast, the more oligotrophic Lake Sarnen contributed to 3.2 ± 4.2 gN m−2 year−1, and had removed only one-third of the areal N load. The historic dataset of the eutrophic lake revealed a close linkage between annual loads of dissolved N (DN) and removal rates (NRR = 0.63 × DN load) and a significant correlation of the concentration of bottom water nitrate and removal rates. We further show that the seasonal increase in N removal rates of the eutrophic lake correlated significantly with seasonal oxygen fluxes measured across the water–sediment interface (R2 = 0.75). We suggest that increasing oxygen enhances sediment mineralization and stimulates nitrification, indirectly enhancing denitrification activity.

A meta-analysis of benthic rotifer community structure as a function of lake trophic state

Our understanding of the ecological drivers that control community structure of benthic rotifers is poorly known. By reviewing 21 papers on freshwater benthic rotifers we compiled an inventory of an additional 258 species, 27 genera, and six families not previously listed in the review of benthic, lotic rotifers by Ricci and Balsamo (Freshw Biol 44:15–28, 2000). This raises the number of reported benthic species to 416, ~ 23% of all rotifers. Using selected papers within our dataset we tested two hypotheses: (1) Within lakes of different trophic state benthic rotifer communities differ in their species composition and (2) because rotifer trophi types reflect strong specificity for certain foods, there is a difference in the distribution of trophi types in lakes of different trophic state. We found that the trophic state of water bodies influences species composition of benthic rotifers, but there was no significant difference in the distribution of their trophi types. To aid in understanding community assembly of benthic rotifers, we provide a list of knowledge gaps that future studies could address.

Planktonic Microcrustacean Community Structure Varies with Trophic Status and Environmental Variables in Tropical Shallow Lakes in Malaysia

A study was conducted to evaluate planktonic microcrustacean species composition, abundance, and diversity in lakes with different trophic status and to determine the relationship between microcrustacean community structure and lake environmental conditions. This study hypothesized that there are correlations between eutrophication levels and microcrustacean community structures in a lake. Three shallow lakes of different trophic status (Sembrong, Putrajaya and Subang lakes) were selected for this study. Two-Way Analysis of similarities (ANOSIM) revealed differences in microcrustacean diversity and density amongst lakes, where the hypereutrophic condition in Sembrong lake resulted in the lowest diversity but the highest density of microcrustaceans. Similarity percentage (SIMPER) analysis identified the discriminator species among lakes where the domination of small-sized microcrustaceans was observed in lakes with high levels of eutrophication; the hypereutrophic Sembrong lake (Ceriodaphnia cornuta, 74.0%); the meso-eutrophic Putrajaya lake (Bosmina longirostris, 46.9%; C. cornuta, 19.4%). Chlorophyll a, total phosphorus and water transparency showed significant roles in the distribution of microcrustaceans. The canonical correspondence analysis (CCA) scores indicated that small-sized C. cornuta and B. longirostris were related to the eutrophic conditions of lakes. This study elucidated that the lake trophic status could be one of the main factors contributing to the community restructuring of microcrustaceans in tropical lakes.

Benthic-pelagic coupling in lake energetic food webs

Understanding how energy and matter flow among habitats is a central issue in ecology. In lake ecosystems, benthic-pelagic coupling (B-P coupling) was mainly studied based on the diets of top consumers at a population level or through food chains. However, how B-P coupling operates at the ecosystem level is largely unknown.In the present study, we revealed B-P coupling within an energetic food web framework, combining stable isotope analyses and mass balanced model. We constructed the energetic food webs of two large shallow lakes of different trophic status based on field survey data. We also defined benthic and pelagic components based on the proportion of consumer energy uptake from phytoplankton (benthic: <50%; pelagic:>50%; benthivore: <20%; planktivore:>80%; coupler: 20–80%) and quantified the energy flux through B-P coupling in the two lake food webs.The total consumption was estimated to be 699 t/km2/y in Lake Erhai (mesoeutrophic lake) and 2094 t/km2/y in Lake Dianchi (hypereutrophic lake), and the B-P coupling energy was 405 t/km2/y and 213 t/km2/y, respectively. In these lakes, B-P coupling occurred on multiple trophic levels; lower trophic level consumers contributed the largest proportion (90% and 98%), while top consumers were of limited importance; most coupling links were weak, and energy exchange was highly asymmetric with the total amount of energy exported from benthic part to pelagic part being over 4 folds of the counter flux.The quantity and pattern of B-P coupling vary between the mesoeutrophic and hypereutrophic lakes. In terms of energy flux per unit area, the total system throughput in the mesoeutrophic lake (Lake Erhai) was 3.73 times of that in the hypereutrophic lake (Lake Dianchi), while the proportion of coupling energy was much lower in the former (19%) than the latter (31%). A greater energy flux through pelagic-to-benthic pathways was found in the hypereutrophic lake, and most of the coupling energy was contributed by consumers at higher trophic levels. Besides, the coupling strength was stronger in the hypereutrophic than the mesoeutrophic lake.We showed for the first time how B-P coupling operates in lake energetic food webs. Our results provided new insights into understanding the energy flux through B-P coupling of lake ecosystems, and how such coupling could be changed by environmental disturbances. We also provided a new approach to reveal habitat coupling within an energetic food web framework.

Phytoplankton and Bacterial Community Structure in Two Chinese Lakes of Different Trophic Status.

Phytoplankton are the primary producers at the basis of aquatic food webs, and bacteria play an important role in energy flow and biochemical cycling in aquatic ecosystems. In this study, both the bacterial and phytoplankton communities were examined in the oligotrophic Lake Basomtso and the eutrophic Lake South (China). The results of this study showed that the phytoplankton density and diversity in the eutrophic lake were higher than those in the oligotrophic lake. Furthermore, Chlorophyta (68%) and Cryptophyta (24%) were the dominant groups in the eutrophic lake, while Bacillariophyta (95%) dominated in the oligotrophic lake. The bacterial communities in the waters and sediments of the two lakes were mainly composed of Proteobacteria (mean of 32%), Actinobacteria (mean of 25%), Bacteroidetes (mean of 12%), and Chloroflexi (mean of 6%). Comparative analysis showed that the abundance of bacteria in the eutrophic lake was higher than that in the oligotrophic lake (p < 0.05), but the bacterial diversity in the oligotrophic lake was higher than that in the eutrophic lake (p < 0.05). Finally, the bacterial abundance and diversity in the sediments of the two lakes were higher than those in the water samples (p < 0.05), and the Latescibacteria and Nitrospinae groups were identified only in the sediments. These results suggest that both the phytoplankton and bacterial communities differed considerably between the oligotrophic lake and the eutrophic lake.

Microbialite crusts in Irish limestone lakes reflect lake nutrient status

Many Irish limestone lakes contain a characteristic benthic crust, a microbialite layer composed of cyanobacteria, algae and inorganic mineral deposits. Previous work suggests that these crusts are influenced by lake nutrient status. The purpose of this paper was to test this hypothesis. In order to do this, it was first necessary to describe crust structure, chlorophyll content and species composition. Relative abundances of species were examined, as well as crust cover, thickness and organic content. A diverse community of filamentous and coccoid cyanobacteria was recorded, with chlorophytes and diatoms also present. Crusts were found to contain a high percentage (>75% of dry mass) of mineral particles, bound together by various filamentous cyanobacteria. Significant differences were shown between lakes of different trophic states, based on analyses of biological and physical factors. Strong correlations were found between total P, crust chlorophyll and crust community structure.

Microbialite crusts in Irish limestone lakes reflect lake nutrient status

Many Irish limestone lakes contain a characteristic benthic crust, a microbialite layer composed of cyanobacteria, algae and inorganic mineral deposits. Previous work suggests that these crusts are influenced by lake nutrient status. The purpose of this paper was to test this hypothesis. In order to do this, it was first necessary to describe crust structure, chlorophyll content and species composition. Relative abundances of species were examined, as well as crust cover, thickness and organic content. A diverse community of filamentous and coccoid cyanobacteria was recorded, with chlorophytes and diatoms also present. Crusts were found to contain a high percentage (>75% of dry mass) of mineral particles, bound together by various filamentous cyanobacteria. Significant differences were shown between lakes of different trophic states, based on analyses of biological and physical factors. Strong correlations were found between total P, crust chlorophyll and crust community structure.

Eutrophication exacerbates the impact of climate warming on lake methane emission

Net methane (CH4) emission from lakes depends on two antagonistic processes: CH4 production (methanogenesis) and CH4 oxidation (methanotrophy). It is unclear how climate warming will affect the balance between these processes, particularly among lakes of different trophic status. Here we show that methanogenesis is more sensitive to temperature than methanotrophy, and that eutrophication magnifies this temperature sensitivity. Using laboratory incubations of water and sediment from ten tropical, temperate and subarctic lakes with contrasting trophic states, ranging from oligotrophic to hypereutrophic, we explored the temperature sensitivity of methanogenesis and methanotrophy. We found that both processes presented a higher temperature sensitivity in tropical lakes, followed by temperate, and subarctic lakes; but more importantly, we found that eutrophication triggered a higher temperature sensitivity. A model fed by our empirical data revealed that increasing lake water temperature by 2 °C leads to a net increase in CH4 emissions by 101–183% in hypereutrophic lakes and 47–56% in oligotrophic lakes. We conclude that climate warming will tilt the CH4 balance towards higher lake emission and that this impact will be exacerbated by the eutrophication of the lakes.

Quantitative description of respiration processes in meso-eutrophic and eutrophic freshwater environments

We propose a modification of measurement methodology allowing the overall respiration rate (VResp) close to the in situ conditions; size of the labile, respirable organic matter pool (OMResp); and its turnover time (Tt) to be calculated. In addition to the respiration of dissolved substrates by free-living bacteria, the respiration of attached bacteria and other planktonic organisms is also taken into account. In case study we evaluated the modified, quantitative description of respiration processes in surface waters of lakes of different trophic status: mezzo-eutrophic and eutrophic. In both types of studied environments, VResp oscillated between 1.0 μmol C l−1 h−1 and 3.0 μmol C l−1 h−1, and the size of the OMResp pool varied from 39.3 μM C to 828.7 μM C. Despite of higher OMResp concentrations in eutrophic lakes, we found a lower susceptibility of OM to respiration processes in eutrophic than in meso-eutrophic lakes but similar VResp in both types of lakes. We conclude that the proposed method allows a fast quantitative description of labile organic matter utilization by aerobic aquatic microorganisms.

Microbial colonization and decomposition of invasive and native leaf litter in the littoral zone of lakes of different trophic state

Riparian invasion by non-native trees may lead to changes in the quality of leaf litter inputs into freshwater ecosystems. Different plant species may affect the community of decomposers and the rate of litter decay in different ways. We studied the microbial colonization and decomposition of leaf litter of the invasive to Lithuania Acer negundo and native Alnus glutinosa during 64-day litterbag experiments in the littoral zones of mesotrophic and eutrophic lakes. The decomposition of A. negundo leaf litter proceeded faster than that of A. glutinosa irrespective of differences in the trophic conditions of the lakes. The amount of terrestrial and cellulose-degrading fungi (during the initial period) and bacterial numbers (during the experiment) were higher on A. negundo leaves than on A. glutinosa in both lakes. Differences in the assemblages of aquatic fungi colonizing the leaves of both types might be one of the reasons causing variation in their decay. The trophic conditions of the lakes did not significantly determine the extent of differences in decomposition rates between the two leaf species, but affected the microbial decomposers. The sporulation rate and diversity of aquatic fungi, especially on A. glutinosa leaves, was higher in the mesotrophic lake than in the eutrophic lake, while heterotrophic bacteria were more numerous on the leaves in the eutrophic lake. Generally, differences in the colonization dynamics of heterotrophs and the faster decay of A. negundo litter than of A. glutinosa suggest that the replacement of native riparian species such as the dominating A. glutinosa by invasive A. negundo may cause changes of organic matter processing in the littoral zones of lakes.