Cyanobacteria respond to trophic status in shallow aquatic ecosystems.

Small and shallow water bodies are particularly sensitive to adverse conditions connected with anthropogenic eutrophication. As model systems, ponds are a good object for ecological research and monitoring of global environmental changes. We examined cyanobacteria along with other groups of algae versus zooplankton and abiotic characteristics of water in 51 aquatic ecosystems exposed to anthropogenic pressure (from natural forest to highly disturbed field ponds) with 3 distinct trophic groups: meso-, eu- and hypertrophic. This study aimed to define how different levels of trophy affect pond-specific cyanobacteria assemblages and to identify species responding to particular trophic states. We demonstrated that trophic type determined the occurrence of certain cyanobacteria species. From among 78 identified taxa, shade- and turbid mixed adapted were the most numerous. Eutrophic ponds had the highest cyanobacteria species and diversity and abundance of zooplankon. Dominating species such as Chroococcus minimus, Anagnostidinema amphibium, Phormidium granulatum or Komvophoron minutum preferred mesotrophic, while e.g. Jaaginema subtilissimum, Limnolyngbya circumcreta, Limnothrix vacuolifera or Romeria leopolienis eutrophic waters and these were not grazed by filtrators. Only 3 species (Aphanizomenon flos-aquae, Dolichospermum circinale, Planktothrix agardhii) were associated with hypertrophic ponds. Therefore, we assume that cyanobacteria taxa have a high indicative potential to distinguish between trophic type of ponds. Reynolds Functional Groups also exhibit responses to changes in water quality. It was partucularly evident in the case of cyanobacteria representatives of codon M which was attributed to eutrophic ponds. Advancing our understanding about trophic preferences of cyanobacteria is crucial, especially in the era of global warming and the persistent issue of water eutrophication, when problems with harmful cyanobacterial blooms are intensifying. The research findings have ecological significance and management implications, highlighting the often-overlooked importance of pond ecosystems in maintaining overall water quality.

Can the concentration of elements in wild-growing mushrooms be deduced from the taxonomic rank?

The mineral composition of wild-growing mushroom species is influenced by various environmental factors, particularly the chemical properties of the soil/substrate. We hypothesised that element uptake might also correlate with taxonomic classification, potentially allowing us to predict contamination levels based on mushrooms within the same taxonomic rank. This study compared the mineral composition (Ag, As, Ba, Ca, Cd, Co, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Se, and Zn) of 16 saprotrophic mushroom species from 11 genera across 4 families and 2 orders. Among these were 13 edible and 3 inedible mushrooms, all collected from natural, wild stands in a forest in central-western Poland between 2017 and 2020. Phallus impudicus exhibited the highest mean content of Ba (together with Phallus hadriani) (6.63 and 8.61 mg kg-1, respectively), Ca (with Paralepista gilva and Stropharia rugosoannulata) (803, 735 and 768 mg kg-1, respectively), Cd (with Lycoperdon perlatum) (3.59 and 3.12 mg kg-1, respectively), Co (0.635 mg kg-1), and Fe (with P. hadriani and S. rugosoannulata) (476, 427 and 477 mg kg-1, respectively), while Macrolepiota mastoidea showed the highest content of Ag (1.96 mg kg-1), As (with Coprinus comatus) (1.56 and 1.62 mg kg-1, respectively) and Cu (with Macrolepiota procera and Chlorophyllum rhacodes) (192, 175 and 180 mg kg-1, respectively). Comparing the content of the analysed elements in the genera represented by at least two species, a similarity was observed, the same as the mean concentration in soil under these species. Soil characteristics could be a superior factor that overshadows the impact of the mushroom genus on the elements accumulation, obscuring its role as a determinant in this process. The results are not definitive evidence that belonging to a particular taxonomic rank is a prerequisite condition affecting the accumulation of all elements. A closer focus on this issue is needed.

How can top-down and bottom-up manipulation be used to mitigate eutrophication? Mesocosm experiment driven modeling zooplankton seasonal dynamic approach in the trophic cascade.

Eutrophication leads to algae blooms and reduces the transparency of water bodies, which seriously affects water quality and ecosystem equilibrium, especially in shallow water body ecosystems (SWE). Controlling foodwebs by manipulating fish and macrophytes provides a feasible method to mitigate the effects of eutrophication. The response of zooplankton as the primary consumer to biomanipulation is mostly conceptualized and lacks detailed observation. Mesocosm experiments that altered the biomass of planktivorous fish and macrophytes were set up and their boundary conditions were extended into a series of scenarios for modeling biomanipulation. Thus, this study utilizes a one-dimensional lake ecosystem model Water Ecosystems Tool (WET) which considered each zooplankton group: rotifers, cladocerans, and copepods, to predict the seasonal dynamic effects of biomanipulation on zooplankton in SWE, and the model results are analyzed in comparison with the mesocosm results. Observed data from mesocosm experiments set up in a temperate pond, including water temperature, dissolved oxygen (DO), total nitrogen (TN), total phosphorus (TP), chlorophyll a (Chl a), macrophytes, zooplankton, and fish, were used to calibrate and validate the models. The modeled results showed that in spring and summer zooplanktivorous fish removal would increase all three categories of zooplankton and consequently cause a decrease of phytoplankton, whilst an increase in fish biomass would increase phytoplankton, and concomitantly water turbidity. However, in autumn, rotifers and phytoplankton increased in response to fish removal, but cladocerans and copepods decreased, 27% and 41%, respectively. Across all three vegetated seasons, increasing the biomass of macrophytes revealed a similar pattern: all three categories of zooplankton increased and phytoplankton subsequently decreased. Our study proposes a "fish-zooplankton-macrophyte-phytoplankton" trophic cascade and quantitatively predicts the dynamics of each zooplankton group under biomanipulation through this pathway, and provides support for establishing macrophyte beds and removing zooplanktivorous fish (in spring and summer) as an effective approach to mitigate eutrophication.

Spatial heterogeneity of chemistry of the Small Aral Sea and the Syr Darya River and its impact on plankton communities.

The shrinking of the Aral Sea represents one of the greatest ecological disasters of modern time. The data on the surviving northern part (Small Aral) is scarce and requires an update. This study aimed to analyze the chemistry, phyto- and zooplankton composition, and their relation in the waters of the Small Aral and its tributary, Syr Darya River. The chemistry of both ecosystems was significantly different. Small Aral was characterized by higher ionic concentrations, salinity, and electric conductivity and more significant spatial variation of chemical properties. The area near the river mouth was more pristine, while the ions concentration and salinity in the distant bays were much higher (>10‰). The highest concentrations of nitrates and total phosphorus in the Syr Darya were observed near Kyzylorda, indicating urban pollution. Overall, 109 phytoplankton taxa were identified in both ecosystems, with diatoms, green algae, and cyanobacteria being most abundantly represented. Oligohalobes dominated, but no polyhalobes and euhalobes algal species were identified. In total, 27 taxa of zooplankton were identified in both studied ecosystems, with the domination of rotifers over microcrustaceans. An exceptionally high level of dominance (65-91%) of rotifer Keratella cochlearis in the Syr Darya was found. The phyto- and zooplankton species richness was higher in the Syr Darya. Plankton communities of the Small Aral reflected horizontal variability of chemical properties. The total phosphorus promoted the prevalence of diatoms, rotifers, and crustaceans. Increased nitrogen concentration promoted cyanobacteria, chlorophytes, cryptophytes and chrysophytes, and rotifers Keratella cochlearis and K. quadrata. The abundance of dinophytes, diatoms Navicula cryptotenella and Cocconeis placentula, green algae Mychonastes jurisii and rotifer Keratella tecta was driven by the higher alkalinity and conductivity/salinity levels. The results represent a reference point for future monitoring of the area and add to understanding the complexity of biological transformations in the Aral Sea and its tributary.

Chlorophytes response to habitat complexity and human disturbance in the catchment of small and shallow aquatic systems.

Human-originated transformation in the catchment area may be reflected in the water quality and ecological state of the aquatic environment. Chlorophytes, the most common and diverse group of microalgae, may be a valuable tool for studies of small water bodies, ecosystems poorly recognized but extremely sensitive to the climate changes. Here we investigated the response of the chlorophytes to abiotic and biotic factors in different habitats and ponds' catchments. Chlorophytes demonstrated a prevalence towards a specific type of catchment area. Field ponds supported chlorophytes typical for nutrient-rich/high-organic and shallow well-mixed waters. Forest ponds supported high chlorophyte diversity. A high importance of desmids, tolerant to light deficiency, confirms their preferences towards lower pH and lower trophic state in the forest ponds. Habitat type strongly impacted the distribution of chlorophytes. Great abundance and fertile-water species were associated with the open water, whereas aquatic plants hosted relatively low chlorophyte abundance which is a derivate of the filtrators grazing as well as the nutrient uptake and shadowing by macrophytes. Macrophyte-dominated zones created favorable conditions for some periphytic desmids and filamentous chlorophytes, species preferring lower trophic state and co-occurring with zooplankton. We assume that cosmopolitan chlorophytes can be adapted for determination of the ecological value of small water bodies, including the level of habitat heterogeneity. But chlorophytes clearly react to the level of human impact in the ponds' catchment, both specific species and functional groups. Thus, we recommend them, particularly desmids, for water quality state assessment in ponds.

Road traffic and abiotic parameters of underlying soils determine the mineral composition and nutritive value of the mushroom Macrolepiota procera (Scop.) Singer.

The effectiveness of accumulating mineral elements by wild-growing mushrooms depends mainly on species, their growth place, and the underlying soil's chemical characteristics. The aim of the study was to determine the effect of road traffic and the role of chemical characteristics of soil on the mineral composition of Macrolepiota procera fruit bodies growing in close proximity to a road and an adjacent forest during a four-year period. The concentrations of the majority elements (mainly Al, Cd, Co, Cr, Cu, Pb, Ti, and Zn) in the soil near the road were significantly higher than those in the forest soil, which was reflected in the fruit bodies which contained a higher amount of these elements. While the accumulation of heavy metals and other elements in the M. procera fruit bodies did not depend on the total soil organic carbon content, the degree of their decomposition determined by the C:N ratio and the individual fractions of organic carbon had a significant influence. Our studies show that soil properties are highly variable in the natural habitats of M. procera, which affects the efficiency of element accumulation. Macrolepiota procera fruit bodies growing in soil with similar chemical properties were characterized by different mineral compositions. Moreover, the obtained results indicate that the fruit bodies of edible M. procera, not only those close to roads but also at a greater distance, may contain significant amounts of toxic As and Cd, which could pose a health risk if consumed. Although most studies describing the mineral composition of M. procera fruit bodies have found no evidence to question the safety of their consumption, this species can effectively accumulate selected elements when growing immediately beside roads or in their close proximity.

Anthropogenic contamination leads to changes in mineral composition of soil- and tree-growing mushroom species: A case study of urban vs. rural environments and dietary implications.

Because wild-growing edible mushroom species are frequently consumed, a knowledge of their mineral composition is essential. The content of elements in mushrooms and their possible beneficial or harmful effect may be influenced by the human-impacted environment. Thus, the aim of the study was to analyse the mineral composition of the soil, trees, and especially soil- and tree-growing mushroom species collected from within a city and from rural areas. Due to potentially higher pollution in urban areas, we assumed that mushrooms from a city environment will contain higher levels of mineral elements than those from rural areas and that the high content will be attributed to greater contamination of city soils. Significantly higher concentrations of several elements in soils (Ca, Ba, Bi, Hg, Pb, Sb, Sr, W and Zr) and trees (Ag, Bi, Ce, Co, Mn, Mo, Nd, Pr, Ta, Tm and W) were observed from the samples collected in the city. Additionally, significantly higher contents of Ag, Fe, Hg, Mn, Mo, Sr, Y and Zn in soil-growing, and Al, As, Ba, Cr, Fe, Hg, Ni, Pb, Sr, Ta and Zn in tree-growing mushroom species were recorded from the urban area. These differences formed the basis for the observation that the content of elements in urban mushrooms is generally higher than in those from rural areas. However, a higher content of several soil elements does not necessarily mean that there will be a significantly higher content in fruit bodies. There was also no real risk of consuming soil-growing mushroom species collected in recent years from the city, suggesting that this practice may still be continued.

Toxicological risks and nutritional value of wild edible mushroom species -a half-century monitoring study.

The content of major- and trace elements in wild-growing mushrooms has been subject to numerous studies, but the data on long-term trends in this regard are scarce. The aim of research was to determine the content of 34 elements in four edible mushroom species Boletus edulis, Imleria badia, Leccinum scabrum and Macrolepiota procera, and associated soil collected from Polish forests between 1974 and 2019. As initially hypothesized, the element concentration in the studied soil revealed an increasing trend and was positively correlated with their levels found in fruit bodies. Bioconcentrafion Factor values exceeding 1 were documented for all mushroom species for K, P, Ag, Cd, Cu, Hg, and Zn. When compared to the Adequate Intakes, all the mushroom species were found to be a good dietary source of K, P, and Zn (range of 6260-8690, 6260-8690 and 97-135 mg kg-1 dry weight (dw), respectively), and B. edulis and I. badia a moderate source of Fe (mean 71.5 and 76.5 mg kg-1 dw, respectively), B. edulis of Mn and Mo (mean 20.0 and 0.42 mg kg-1 dw, respectively), while L. scabrum and M. procera a source of Cu. Consumption of the studied mushrooms would not lead to significant exposure to Al, As, Cr, or Ni. Considering that wild mushrooms will continue to be collected in Poland, one should bear in mind that they are a limited source of minerals in the human diet while their frequent, regular consumption, associated with exposure to selected toxic elements, should not be recommended.

Multiannual monitoring (1974-2019) of rare earth elements in wild growing edible mushroom species in Polish forests.

There is a growing demand for rare earth elements (REEs) due to their use in modern technologies, and this may result in their emission to the environment. This is the first long-term study to monitor the content of REEs in four edible mushroom species. Over 21,900 samples of fruit bodies (sporocarps) of Boletus edulis, Imleria badia, Leccinum scabrum and Macrolepiota procera and their underlying soils, collected between 1974 and 2019 from 42 forest sites in Poland were examined in an attempt to understand the time evolution of the presence of REEs in the environment. In general, I. badia and B. edulis displayed a greater total content of REEs on mg per kg basis than L. scabrum and M. procera. A gradual increase in REEs in the studied mushrooms as well as associated forest soil samples was observed over the monitored period. Both levels were also highly correlated. Regardless of the considered period, human consumption of these mushrooms would not contribute significantly to dietary exposure to REEs. Wild growing mushroom species studied over a long time period may be a good bioindicator of REE migration to the environment.

An Ensemble Kalman Filter approach to assess the effects of hydrological variability, water diversion, and meteorological forcing on the total phosphorus concentration in a shallow reservoir.

Total phosphorus (TP) is a vitally important water quality index in shallow reservoirs and is closely connected with hydrological variability, anthropogenic water diversion and meteorological forcing. However, it is still unclear to what extent the TP concentration in a complex shallow reservoir system attributes to each type of forcing. To resolve this issue, this study proposed a TP concentration contribution index (TPI) to assess the contribution of each forcing, using the data assimilation (DA) method, the Ensemble Kalman Filter (EnKF), which was applied in the shallow Yuqiao Reservoir, China. The EnKF model was conducted based on the Vollenweider model and logistic regression models with datasets of 1989-2015. The results showed that human-originated activities forcing (water diversion) contributed the maximum TPI (40%), followed by hydrological variability forcing (37%). Finally, meteorological forcing (air temperature and wind included) only accounted for 23%. Furthermore, the seasonal analyses also showed that the TPI of hydrological variability dominated in spring and winter, with 65% and 73% respectively. However, the contributions of meteorological forcing (air temperature and wind) accounted for a larger proportion of 63% and 57% in summer and autumn. The benefit of our EnKF model denoises the Gaussian noise contained in observation and simulation, which offers a chance to isolate and identify even a minor driving factor (i.e., meteorological forcing) from a complex river and lake system with limited data. The study provides a method to assess the influence of direct and indirect forcing on TP concentration in shallow reservoirs from a quantitative perspective. Thus, it may serve as a useful tool for water quality management in water-receiving systems.

Cyanobacteria in small water bodies: The effect of habitat and catchment area conditions.

Cyanobacteria are an important component of microalgae communities in aquatic ecosystems, however, their response to environmental factors in different habitats and catchment areas of small water bodies is still not well recognised. We examined ponds from two types of surroundings (field vs. forest) in order to find the best triggers for the distribution of cyanobacteria species, and analysed different habitats (open water and macrophyte-dominated zones) to find the habitat preferences of cyanobacteria species. Our results underline the important role of habitats in the determination of the abundance of cyanobacteria species in small water bodies. Cyanobacteria as a group preferred macrophyte-dominated sites with stable water column conditions, which to lesser extent were inhabited by representatives of other systematic groups of algae. The co-occurrence of many cyanobacteria species and zooplankton in the studied ponds may have indirectly resulted from biotic interactions in the food web. In the open water a positive relationship between zooplankton and cyanobacteria suggests stimulation of their development through the elimination of smaller edible taxa or by nutrient resupply through zooplankton excretion. The type of catchment area also impacted the cyanobacterial community. Field ponds with significantly higher values of pH and NO3 were characterised by a higher abundance of cyanobacteria compared with ponds within the forest catchment. A positive relationship between pH and cyanobacteria indicates that they raise pH during photosynthesis. However, some species were negatively associated with water temperature and occurred exclusively only in forest ponds. The study revealed that cyanobacteria in small water bodies can be a valuable indicator of important ecosystem conditions. Despite the fact that their prevalence in agricultural ponds may confirm their potential as an indicator of pollution, their high diversity associated with macrophytes contributes to an increase of overall landscape biodiversity.

Ecological value of macrophyte cover in creating habitat for microalgae (diatoms) and zooplankton (rotifers and crustaceans) in small field and forest water bodies.

Due to their small area and shallow depth ponds are usually treated as a single sampling unit, while various microhabitats offer different environmental conditions. Thus, we tested the effect of different habitat types typically found within small ponds on the microalgae and zooplankton communities. We found that submerged macrophytes have the strongest impact on microalgae and zooplankton communities out of all the analysed habitats. Some epontic diatoms (e.g. Fragilaria dilatata, Cymbella affinis) and littoral-associated zooplankton species (e.g. Simocephalus vetulus, Lecane bulla) were significantly related to elodeids. However, pelagic species (e.g. bosminids) preferred less complex helophytes, which suggests that the most heterogeneous elodeid habitats were not an anti-predator shelter for cladocerans. Selection of different macrophyte types by taxonomically various organisms suggests that it is not only macrophyte cover that is desired for healthy aquatic environment but that a level of habitat mosaic is required to ensure the well-being of aquatic food webs. Species-specific preferences for different types of macrophytes indicate the high ecological value of macrophyte cover in ponds and a potential direction for the management of small water bodies towards maintaining a great variation of aquatic plants. Moreover, the type of surrounding landscape, reflecting human-induced disturbance (28 field ponds) and natural catchment (26 forest ponds), significantly influenced only zooplankton, while diatoms were affected indirectly through the level of conductivity. Nutrient overload (higher content of TRP) and increased conductivity in the field landscape contributed to a rise in microalgae (e.g. Amphora pediculus, Gomphonema parvulum) and zooplankton (e.g. Thermocyclops oithonoides, Eubosmina coregoni) abundance. An awareness of the responses of both components of plankton communities to environmental factors is necessary for maintaining the good state of small water bodies in various types of landscape.