Anthropogenic Eutrophication Research Articles

Role of climate variability on deep-water dynamics and deoxygenation during sapropel deposition: New insights from a palaeoceanographic empirical approach

Modern marine settings are experiencing rapid deoxygenation mainly forced by global warming and anthropogenic eutrophication. Therefore, studies that assess the role of climate variability in large spatiotemporal deoxygenations during past climate changes are needed to better comprehend the consequences of the current global warming and ocean deoxygenation. In this respect, deep marine sediments associated to past oxic-to-anoxic transitions are useful palaeoarchives for understanding the interplay between climate variability, deep-water dynamics and large-scale deoxygenation. Moreover, they can offer long-term perspectives to modern marine settings that are suffering oxygen depletion due to climate change and anthropogenic pressure. In particular, sapropel layers from the Middle Pleistocene to the Holocene are excellent palaeoarchives of past large-scale deoxygenation events, since (i) they occurred during a similar Mediterranean hydrogeographic configuration to the present, (ii) have a robust chronological control, and (iii) previous studies have reconstructed the climate conditions that ruled during their deposition. In this work, we have applied empirical palaeoceanographic conceptual models to five sapropels (S1, S5, S6, S7 and S8) in three Eastern Mediterranean (EM) settings. The models suggest that the hydrographic regimes of all studied sapropels can be considered as analogues to those observed in certain modern marine restricted settings. The results obtained support the idea that climate and the degree of surface-water freshening are the primary factors that influence deep-water dynamics in marine restricted settings, that in turn control the frequency and intensity of bottom-water deoxygenation and the stability and depth of the chemocline. The deepest EM sites are the most vulnerable locations to develop bottom-water restriction and deoxygenation. Local hydrogeographic factors play an essential role in the extent and frequency of bottom-water deoxygenation. Particulate shuttling was very intense during sapropel deposition and water-mass exchange between EM and Western Mediterranean controlled the intensity of the basin reservoir effect and Mo budget in EM.

Novel CRISPR/Cas technology in the realm of algal bloom biomonitoring: Recent trends and future perspectives

In conjunction with global climate change, progressive ocean warming, and acclivity in pollution and anthropogenic eutrophication, the incidence of harmful algal blooms (HABs) and cyanobacterial harmful algal blooms (CHABs) continue to expand in distribution, frequency, and magnitude. Algal bloom-related toxins have been implicated in human health disorders and ecological dysfunction and are detrimental to the national and global economy. Biomonitoring programs based on traditional monitoring protocols were characterised by some limitations that can be efficiently overdone using the CRISPR/Cas technology. In the present review, the potential and challenges of exploiting the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas technology for early detection of HABs and CHABs-associated toxigenic species were analysed. Based on more than 30 scientific papers, the main results indicate the great potential of CRISPR/Cas technology for this issue, even if the high sensitivity detected for the Cas12 and Cas13 platforms represents a possible interference risk.

The use of unmanned aerial photography for interpreting the technogenic transformation of the natural environment during the oilfield operation

The traditional approach to monitoring observations of the technogenic processes development in oilfields, which consists in determining the concentration of marker pollutants in various natural environments, does not provide the necessary completeness of information and the efficiency of its receipt. The paper considers an example of expanding the range of observations due to unmanned aerial photography and a number of other methods. Interpretation signs (for panchromatic survey) were determined that register such consequences of technogenic transformation of the natural environment as mechanogenesis, bitumization, and halogenesis. Technogenic mechanogenesis is understood as a physical violation of the integrity of ecosystems, the movement of soils and grounds. Bitumization is expressed in the migration of petroleum hydrocarbons through soils, ground, surface, subsurface, and underground waters, and their destruction. Salt migration in these media is defined as halogenesis. The most reliable indicators are linearly elongated areas of dead forests, dark red spots in drying microdepressions and reservoirs. It was found out that the oilfield impact on the raised bog leads to anthropogenic eutrophication, the introduction of plant species, uncharacteristic coenotic groups, the replacement of subshrubs with grasses, and morphometric changes in forest pine. In the peat deposits of the disturbed area, an unusual interlayer of whitish, undecomposed moss was recorded. The moment of the beginning of a pronounced technogenic transformation was registered in the course of work with the archive of multispectral space images. Continuous remote sensing with the help of unmanned aerial photography and interpretation by sedimentological, geobotanical methods significantly expand the possibilities of studying the technogenic transformation of the natural environment. To ensure environmental safety, it is advisable to develop remote methods and technologies to include them in the environmental monitoring system.

Understanding the relationship between nutrient availability and freshwater cyanobacterial growth and abundance

ABSTRACT Anthropogenic eutrophication is a well-established cause of cyanobacterial blooms in freshwaters. Early studies proposed eutrophication control focused on phosphorus (P) as the key limiting nutrient. The rationale was that nitrogen (N) limitation is alleviated by diazotrophic cyanobacteria that fix atmospheric N. However, more recently, studies suggest that the importance of N fixation may have been overstated, and some call for anthropogenic N control as well as P. Reducing nutrient concentrations below critical levels clearly reduces phytoplankton biomass, but increasing evidence shows that cyanobacterial species can adapt to low and variable nutrient conditions, outcompeting eukaryotic phytoplankton. Strategies supporting cyanobacterial dominance include (1) high affinity P uptake, (2) preferencing cellular storage of P over immediate metabolic utilization for growth, (3) alternation between N fixation and inorganic N utilization as needed, and (4) use of organic nutrients when inorganic nutrient supplies are limited. Predicting the ecological responses of cyanobacteria to nutrients therefore requires more complex models than the simple resource models using inorganic nutrients widely used for contemporary studies. Additionally, many ecological studies are not conducted on timescales relevant to understanding how nutrient fluxes drive physiological responses. We advocate for greater use of high-frequency automated measurements of nutrients and cyanobacteria to address the timescale issue. Additionally, field-based experimental studies focused on nutrient cycling, fluxes, and pools are needed to validate laboratory findings and extrapolate them to in situ conditions. The challenge is to undertake these studies at sufficient spatial and temporal scales to predict large-scale responses of cyanobacteria to nutrients.

Metabolites dynamics exacerbated by external nutrients inputs into a Ceratium hirundinella-dominated bloom in the Pengxi River, Three Gorges Reservoir, China

Secondary metabolites (toxins) production during harmful algal blooms (HABs) further increases the public health risks associated with water quality deterioration from anthropogenic eutrophication. In the present study, the dynamic pattern in the production of metabolites under different nutrient conditions in Ceratium-dominated spring HABs was investigated in Pengxi River, China. Results revealed five (5) important toxins all attributable to the Dinophyceae including azaspiracid 2&4, okadaic acid, tetrodotoxin, brevetoxin, and saxitoxin, each exhibiting certain levels of specificity to the ecosystem enrichments. In effect, while the production of azaspiracid 2 and okadaic acid was N-driven, azaspiracid 4 and tetrodotoxin were enhanced by Ca enrichment. The ambient HABs community structure shows absolute ecosystem dominance by a dinoflagellate, Ceratium hirundinella with relative abundance ((RA = 78.81%, p ˂ 0.05). However, P enrichment triggered a slight shift (p ≥ 0.05) in the HABs species structure within the cyanobacteria strictly represented by Chroococcus minor (RA = 26.60%) and Dolichospermum circinalis (RA = 23.91%) initiating possible emergency dominance. The effect of nutrient addition on biomass production as chlorophyll-a (Chl-a) confirmed a P-limited ecosystem juxtaposed by a secondary limitation by Ca. The significant stimulation on biomass as Chl-a from day 3 through day 4 by N and the multiple enrichments designated as NPFeCa was attributed to luxury consumption rather than limitation following N repletion thus delaying biomass accumulation. The study, therefore, offers useful insights into the dynamic pattern of toxins during spring HABs while it also provides comprehensive knowledge of the HABs impact predictions in the TGR.

Parasite ecology of Carassius gibelio (Bloch, 1782) in Jandari Lake (Georgia)

The aim of the investigation was to study the current structure of the parasitic fauna of the gibel carp (Carassius gibelio) population in the Georgian part of Jandari Lake. In total, 423 young gibel carp collected during 2014-2018 years from Jandari Lake have been subject to parasitological examination. The 20.3% (n=86) of examined fish were invaded by 11 species of parasites belonging to 5 taxonomic groups. The dominant taxonomic groups were discovered to be Protozoa and Monogenea. The eight species were registered for the first time in the gibel carp of freshwater reservoirs in Georgia. In general, young fish were more invaded by the monoxenic species of the direct life cycle. None of the revealed parasites were specific to gibel carp. The parasitic fauna of Jandari Lake is relatively poor, though it is comparatively rich and diverse in spring. Trichodina sp. from Protozoa, Ancyrocephalus sp., Dactylogyrus vastator, Gyrodactylus elegans from Monogenea, and Contracaecum sp. from Nematoda were revealed as the species most sensitive to annual changes. The main factor determining the parasite fauna of gibel carp in Lake Jandari is anthropogenic eutrophication, which changes the qualitative and quantitative composition of zooplankton, the main food source of juvenile fish and intermediate hosts of helminths. The difference in invasion indices between female and male gibel carp was insignificant. The synergetic relationship between some parasitic protozoans and monogeneans was marked.

Blue carbon stocks in southern Africa's Endangered seagrass Zostera capensis

Blue carbon research, although rapidly expanding, still requires site- and species-specific assessments to inform decision-making and policy formation. In this study, C stocks were assessed in the Endangered seagrass Zostera capensis. in the Knysna, Swartkops and Nxaxo estuaries, South Africa. Mean biomass C storage was 2.39 ± 1.42 Mg C ha−1 (similar to the global seagrass average), while 177.65 ± 122.29 Mg C ha−1 was estimated in the top meter of sediment. Sediment organic C content was 0.99 ± 0.45% — markedly lower than the seagrass global average but within the range reported for other Zostera species — and displayed significant spatial variability within and between estuaries. Sediment C was particularly high in the eutrophic Swartkops, likely due to excessive wastewater discharge introducing organic matter to the estuary's seagrass habitats. Based on the C stocks determine in this study, it is estimated that approximately 315 970 ± 217 111 Mg C could be stored in South Africa's 1755 ha of Z. capensis habitats. However, these important blue carbon habitats face multiple threats, particularly climatic events like droughts and floods, and anthropogenic eutrophication. This study has provided the first comprehensive C stock assessment for Z. capensis and contributes to global blue carbon datasets. Furthermore, this work has reinforced the importance of protecting the Endangered seagrass by highlighting the important ecosystem service it provides through climate change mitigation and adaptation.

Water Quality, Toxicity and Diversity of Planktonic and Benthic Cyanobacteria in Pristine Ancient Lake Khubsugul (Hövsgöl), Mongolia.

For the first time, microcystin-producing cyanobacteria have been detected in Khubsugul, which is ancient, pristine and one of the world's largest lakes. The microcystin synthetase genes belonged to the genera Nostoc, Microcystis and possibly Snowella spp. No microcystins were found in the water of the lake. Using the HPLC-HRMS/TOF, five microcystin congeners were identified in biofilms from stony substrates sampled in the coastal zone. The concentration of microcystins in biofilms was low: 41.95 µg g-1 d. wt. by ELISA and 55.8 µg g-1 d. wt. using HPLC. The taxonomic composition of planktonic and benthic cyanobacterial communities was determined by means of microscopy and high-throughput sequencing of 16S rDNA amplicons. Nostocales cyanobacteria dominated benthos of Lake Khubsugul and Synechococcales-plankton. The abundance of cyanobacteria was low both in plankton and benthos; there was no mass development of cyanobacteria. Hydrochemical and microbiological analyses showed that the water in the lake was clean; the number of faecal microorganisms was significantly below the acceptable guideline values. Hydrochemical and hydrophysical parameters, and the concentration of chlorophyll a, were low and within the range of values recorded in the 1970s to 1990s, and corresponded to the oligotrophic state of the lake. There were no signs of anthropogenic eutrophication of the lake and no conditions for the cyanobacterial blooms.

Identifying plant cell wall remnants in detritus of a subtropical wetland with fluorescence labeling

Sediment accretion in wetlands represents a significant carbon burial pathway. While litter studies can quantify the loss rates of plant leaf material, those studies do not provide insight into the specific cell wall polymers being retained or lost within the detrital matrix. The Everglades ecosystem has been dramatically altered due to anthropogenic eutrophication and hydrologic modifications. The results are changes in macrophyte species composition and sediment accretion- and loss- rates. To improve ecological conditions, active management strategies are re-establishing open water slough environments. A question remains about the persistence of new- and old- plant cell wall material in sediments because of active management. In this pilot project we utilized immuno-fluorescence labeling with lectins applied to plant leaf material and detrital flocculent collected from created open and control plots in the Everglades to observe the presence, absence, and overlap of specific cell wall polymers between macrophytes and detrital flocculent in increasingly recalcitrant materials that would most likely contribute to peat accumulation. The persistence and loss of specific polymers between treatment and control plots provided insight into the differing levels of recalcitrance amongst plant cell walls and their relative potential as a carbon sink. This study provides a novel method for testing for the presence and persistence of specific cell wall polymers in detritus to gain a better understanding of plant material persistence in wetland ecosystems.

Live-Dead Shifts in Molluscan Functional Diversity in Coastal Alabama

Abiotic and biotic environmental factors shape species behavioral, physiological, and morphological traits. Shifts in the diversity of these functional traits therefore can serve as an indicator of spatial and temporal changes in environmental conditions. In recent centuries, the delivery of nutrients to coastal ecosystems has increased markedly through changing waste management and land-use practices. Nutrient enrichment has increased rates of primary productivity, resulting in greater organic accumulation on the seafloor and the development of hypoxic conditions in some areas, due to the aerobic decomposition of phytoplankton blooms. Anthropogenic eutrophication and associated hypoxia have been monitored annually in the northern Gulf of Mexico for over four decades, with an emphasis on areas surrounding the Mississippi River Delta. To further understand how anthropogenic eutrophication affects functional diversity in benthic marine communities, we collected live and dead assemblages of bivalve mollusks from surficial sediments at five stations along the -20 meters isobath in coastal Alabama. Bivalves were categorized into functional groups using information about their mobility, fixation, feeding type, substrate preference, and body size. Consistent with our hypotheses, preliminary results indicate a temporal shift from benthic communities dominated primarily by epifaunal and infaunal suspension-feeding species to communities characterized primarily by deposit feeders, many of which dwell on the seafloor surface. Ongoing analyses will help identify the functional traits that are most sensitive to these changing environmental conditions. Understanding functional diversity shifts in the recent past can provide insight into how anthropogenic eutrophication may further impact benthic marine ecosystems in the future.

Impacts of Ocean Deoxygenation on Marine Benthos in the Gulf of Mexico

Ocean deoxygenation is a growing concern globally. Oxygen is less soluble in warm water, and warming temperatures also result in the slowdown of ocean circulation which limits oxygen delivery to deeper waters. Anthropogenic eutrophication has also contributed to the development of hypoxic conditions in many coastal areas. Here we investigate biodiversity structure along an environmental gradient in the Gulf of Mexico to see how patterns of spatiotemporal turnover can inform future biotic response of benthos to ocean deoxygenation. Live and dead assemblages of bivalve mollusks were collected at 15 stations offshore Louisiana, Alabama, and Florida. Abundance and body size data were collected, and specimens were classified functionally using information about feeding, attachment, life position, and body size. Environmental conditions were characterized using multi-decadal mean sea surface temperature (SST), dissolved oxygen (DO), and net primary productivity (NPP), and grain size data from our field samples. Stations in the north-central Gulf affected by Mississippi River discharge are characterized by higher NPP, lower DO, and higher percentages of silt and clay than stations in the northeastern Gulf. Both taxonomic and functional diversity significantly covary with this environmental gradient, with the lowest diversities observed at stations in the core of Louisiana’s “dead zone.” Analyses of spatiotemporal turnover patterns reveal shifts in the dominant feeding mode, with hypoxic environments containing a greater abundance of deposit and mixed feeders, compared with more oxygenated environments that host an abundance of suspension feeders and are characterized by a greater variety of feeding ecologies. Live-dead analyses reveal a shift in taxonomic and functional diversity in coastal Louisiana, that appears to coincide with the onset of anthropogenic eutrophication in these coastal settings.

Environmental Controls on Predator and Prey Body Size in the Northern Gulf of Mexico

The Mississippi River delivers vast quantities of nutrient-rich freshwater to the northern Gulf of Mexico, fueling primary productivity in the coastal zone. Aerobic decomposition of these phytoplankton blooms has resulted in one of the most extensive dead zones on Earth. In contrast, primary productivity and hypoxia are more limited in the northeastern Gulf, where coastal environments are fed by smaller watersheds. How do environmental factors such as primary productivity, oxygen availability, and sea surface temperature shape coastal food webs? Here, we investigate environmental correlates of predator and prey body size in benthic mollusks using Holocene death assemblages. Results of linear mixed effects models indicate that bivalve size and the frequency of drilling predation are both influenced by dissolved oxygen concentrations; bivalve size increases and drilling frequency decreases with declining oxygen levels. Sea surface temperature is positively associated with predator and prey size, whereas net primary productivity has little effect on the size of predators or prey. Predator-to-prey size ratios were not significantly associated with any of the environmental factors considered. Larger bivalves found in oxygen-limited areas may be due to decreased predation pressure, resulting in greater prey longevity. Warmer waters with sufficient dissolved oxygen may also provide suitable growth conditions to increase the size of bivalves and predatory gastropods. Holocene death assemblages can be used to test long-standing hypotheses regarding environmental controls on predator-prey body size distributions through geologic time and provide baselines for assessing the ongoing effects of anthropogenic eutrophication and warming on coastal food webs.

Remotely sensed-based analysis about climatic and landscape change effects on phytoplankton bloom in Barra Bonita Reservoir (São Paulo State, Brazil)

The constant land use and land cover (LULC) changes combined with climatic factors are frequently assigned to anthropogenic eutrophication, one of the main ecological imbalances in aquatic systems characterized by dense phytoplankton proliferation. Beyond the degradation of freshwater ecosystems, some cyanobacterial and algae species produce toxins harmful to living beings. Distinct studies in the literature, usually supported by in situ data, have discussed the influence of LULC and climatic changes on phytoplankton bloom events. In this context, motivated by the importance of understanding the environmental mechanisms assigned to phytoplankton bloom events and considering the difficulties imposed by field data collection, our study focuses on analyzing the mentioned issue only using remotely sensed time series data. For this purpose, we performed a temporal analysis between 1985 and 2018 over a portion of the Barra Bonita Hydroelectric Reservoir, Brazil. Initially, we obtained the landscape occupation, precipitation, and temperature information from the MapBiomas, FLDAS, and CHIRPS projects, respectively. A fully automatic algorithm fed by Landsat image series and supported by Google Earth Engine functions was developed and employed to identify and quantify phytoplankton bloom events. Then, the obtained data were inspected by distinct statistical procedures, including correlation and trend analysis. Although there was an absence of a relationship between the climatic components and the emergence of phytoplankton blooms, it was identified using linear regression models (R2 ≥ 78 % ) an intensification of blooms after the increase in nonnatural forestry areas, reduction of pastures, and advance of agricultural areas. Furthermore, machine learning methods were employed to obtain nonlinear regression models (R2 ≥ 73 % ), making evident that the landscape changes are mainly responsible for the phytoplankton insurgences in the analyzed region. This result agrees with other studies found in the literature and highlights the possibility of investigating anthropogenic eutrophication only using remotely sensed data and automatic algorithms.

Long-term Variations in the Black Sea Population of Smooth Scallop, Flexopecten glaber (Linnaeus, 1758) (Bivalvia: Pectinidae): A Review

Data on the presence and characteristics of smooth scallop Flexopecten glaber (Linnaeus, 1758) aggregations in various parts of the Black Sea shelf (BSS) have been subjected to a retrospective analysis. The waters of the northern (Crimean coast), eastern (Central and North Caucasian), and Anatolian sectors of BSS can be considered the most favorable habitats for smooth scallop, where massive beds of this species were found in the first half of the 20th century. However, no such data are available for the northwestern and western BSS, where freshwater discharges from the Danube, Dniester, and Dnieper form a permanent zone of lower water salinity. The period of decline in the Black Sea scallop population recorded in the 1970s–1990s generally coincided with the well known ecological crisis due to the anthropogenic eutrophication of the Black Sea in the second half of the 20th century. In the late 2000s and the 2010s, the scallop beds in the Crimean BSS showed a tendency to recover, which may be associated with the general improvement of the ecological condition of the Black Sea basin. A similar recovery of scallop beds is expected to occur in the eastern (North and Central Caucasian) and southern BSS, but has not yet been recorded. The results obtained suggest a possibility of downgrading the conservation status of this species in the Red Data Books of the City of Sevastopol and the Republic of Crimea from the `species declining in abundance` to the `species recovering in abundance and distribution`.

Small water bodies in agricultural areas as important habitats for euglenoids in Poland

Temporary water bodies of glacial origin, known as kettle holes, are typical elements of the young moraine landscape in many countries. Unfortunately, they are very exposed to effects of anthropogenic changes, especially in agricultural areas. Due to their small area and depth, as well as to the great fluctuations in water level, they create specific conditions for organisms that inhabit them. Consequently, kettle holes are unique biodiversity hotspots in landscape, rich in some microalgal species, particularly euglenoids (euglenophytes). In this study, the taxonomic composition of euglenoids was studied in three temporary water bodies in an agricultural landscape of Wielkopolska Province (western Poland). In total, 65 euglenoid taxa were identified there during one year. Euglenoids in the investigated field ponds were the most species-rich group of microalgae. They accounted for 26% of the total number of phytoplankton taxa. According to the constancy (frequency) of occurrence most of the species were incidental. The most common taxa were: Trachelomonas volvocina, Euglenaformis proxima, Trachelomonas intermedia, Lepocinclis tripteris, and Lepocinclis acus. The high species richness of euglenoids in aquatic ecosystems of agricultural areas shows how valuable ponds are for preserving local biodiversity and for aquatic food webs. The small water bodies in farmlands should be protected against progressive anthropogenic eutrophication and degradation.

Dynamics of phytoplankton in the coastal waters at Vladivostok in 2019–2021

Structure and abundance of phytoplankton community in the Sportivnaya Harbour and Paris Bay in Vladivostok (western coast of the Japan Sea) was monitored from October 2019 to December 2021. In total, 130 and 144 phytoplankton taxa were identified in these two areas, respectively. The overall cell abundance ranged from 1.3 · 103 to 19 · 106 cells/L (on average 21 · 104 and 84.5 · 104 cells/L); the total phytoplankton biomass — from 3.0 mg/m 3 to 38.5 g/m 3 (on average 0.8 and 2.6 g/m 3 , respectively, by areas). The long-term observations were made for the first time in the Sportivnaya Harbour. The community composition was typical of eutrophic waters, with usual seasonal succession in the Paris Bay but frequent blooms in the Sportivnaya Harbour, when diatoms were replaced by flagellates and filamentous cyanobacteria. Such dynamics is presumably caused by anthropogenic eutrophication due to uncontrolled wastewater discharge.

Isolation and Characterization of Arylamidase-Producing Pseudomonas Alcaligenes from the Water of Al-Asfar Lake, Al Ahsa Oasis, Saudi Arabia

Al-Asfar Lake is an important shallow lake that suffered greatly from anthropogenic eutrophication; therefore, it received considerable interest for economic and environmental purposes. Therefore, the current study aimed to investigate the presence of P. alcaligenes based on culture-dependent methods and detect this enzyme activity by the VITEK biochemical tests. The water sample was collected from the lake, serially diluted through sterile saline, and then inoculated and spread onto CHROMagar media and Mueller Hinton agar media. Then purified by the single selection of all different types of colonies by streaking to obtain well-isolated colonies The P. alcaligenes and the enzyme has been successfully identified with a probability of 95% by VITEK 2® COMPACT automated system after determining the Gram stain characteristic for the isolate under a microscope This study proved the existence of P. alcaligenes species that have never been reported previously in Al-Asfar Lake. Therefore, P.alcaligenes species can be an ideal candidate to take advantage of in pollutant biodegradation and to be invested in bioremediation applications to enhance environmental sustainability, in the future. How to Cite: Abeer T. Al Mousa, Ashraf Y. Khalifa, Munirah F. Aldayel, 2022. "Isolation and Characterization of Arylamidase-Producing Pseudomonas Alcaligenes from the Water of Al-Asfar Lake, Al Ahsa Oasis, Saudi Arabia." Journal of Agriculture and Crops, vol. 9, pp. 122-129.

Changes in water chemical composition in Lake Vedlozero and one of its bays as a result of anthropogenic eutrophication

Lake Vedlozero is an accumulating system of a variety of anthropogenic impacts. Since the 1970s, significant changes have occurred in the landscape structure of stream catchments in the southeastern and western parts of the lake’s drainage basin. Deforestation, conversion to arable land and drainage have enriched the lake water with nutrients and organic matter. The northeastern bay of the lake receives substantial amounts of wastewater from the village of Vedlozero and water from the River Vokhtozerka, affected by agriculture in the catchment. High average annual concentrations of total phosphorus (47–173 μg/l) in the water of the bay cause continuous blooming during the open water period. Blooming intensively in the bay, blue-green algae (cyanobacteria) release toxic substances (neuro-, hepato-, and dermatotoxins) dangerous for humans and animals. Massive development of cyanobacteria in the northeastern bay of Lake Vedlozero in summer now causes skin disorders, specifically allergic dermatitis, in Vedlozero village inhabitants (especially children) who swim in the lake.

PRIORITY DIRECTIONS FOR LONG-TERM PLANNING OF NATURAL ECOSYSTEMS IN THE SUBURBAN AREA OF MINSK

An assessment of the actual organization of natural ecosystems in the suburban area of Minsk is given. Forests predominate among them. The distribution of forests shows an inverse dependence on the distance to the city. The forest cover is minimal in the 20-kilometer zone closest to the city, the fragmentation of forests, on the contrary, is the highest. This belt also accounts for the placement of most reservoirs for water management and recreational purposes. They are built on small rivers and have low resistance to external influences and high dependence on the ecological state of the catchment basins. Perspective threats to natural ecosystems caused by an increase in anthropogenic loads on them due to the formation of the Minsk urban agglomeration, as well as climate change, have been identified. They will increase the risks of developing these ecosystems, air and water pollution, forest death, natural fires, anthropogenic eutrophication of water
 bodies, etc. Priority directions for planning natural ecosystems, adequate to the long-term threats and environmental and resource needs of the city, are proposed. They include, firstly, the formation of a natural framework on their basis, the cores of
 which should be not only local specially protected natural areas, but also the main water bodies with adjacent forests, and
 secondly, the rationale for planning measures in relation to individual types natural ecosystems for various parts of the suburban area. For the part closest to the city, their preservation, ensuring interconnection and purposeful transformation are of
 priority importance, for the remote part – compliance with environmentally acceptable modes of use.

Agricultural conservation practices could help offset climate change impacts on cyanobacterial harmful algal blooms in Lake Erie

Harmful algal blooms (HABs) are a recurring problem in many temperate large lake and coastal marine ecosystems, caused mainly by anthropogenic eutrophication. Implementation of agricultural conservation practices (ACPs) offers a means to reduce non-point source nutrient runoff and mitigate HABs. However, the effectiveness of ACPs in a changing climate remains uncertain. We used an integrated biophysical modeling approach to predict how Lake Erie cyanobacterial HAB severity (bloom biomass) may change under several climate and ACP implementation scenarios, using western Lake Erie and its largely agricultural watershed as our study system. An ensemble of general circulation model projections was used to drive spatially explicit land use and hydrology models of the Maumee River watershed, the output of which informed a predictive model of Lake Erie HAB severity. Results show that, in the absence of changes in ACPs, the frequency of severe HABs is projected to increase during coming decades, owing to increased inputs of nutrients from the watershed. These anticipated increases are due to increased total precipitation and more frequent higher-magnitude rainfall events. While further implementation of ACPs appears capable of reducing severe HAB events, widespread implementation would be necessary to reduce HAB severity below current management targets. This study highlights how continued climate change will only exacerbate the need for land management practices that can reduce nutrient runoff in agriculturally dominated ecosystems, such as Lake Erie. It also shows how interdisciplinary, biophysical modeling approaches can help identify strategies to mitigate HABs in the face of anthropogenic stressors.