Genetic diversity of <Emphasis Type="Italic">Microcystis</Emphasis> blooms (Cyanobacteria) in recently constructed reservoirs in Tigray (Northern Ethiopia) assessed by rDNA ITS

The cyanobacterium Microcystis is notorious for forming extensive and potentially toxic blooms in nutrient-rich freshwater bodies worldwide. However, little is known about the factors underlying the genetic diversity and structure of natural Microcystis populations, despite the fact that this knowledge is essential to understand the build-up of blooms. Microcystis blooms are common and occur year-round in Africa, but are underinvestigated in this continent. We studied the genetic diversity and structure of Microcystis populations in 30 man-made reservoirs in Tigray (Northern Ethiopia) using Denaturing Gradient Gel Electrophoresis of the 16S–23S rDNA internal transcribed spacer (ITS) region and assessed the importance of local environmental conditions and geographic position of the reservoirs for the observed patterns. The analyses showed that both regional and local Microcystis ITS diversity in these recently constructed reservoirs was relatively low, with several dense blooms containing only a single ITS type. Especially one non-toxic ITS type dominated a considerable fraction of Microcystis blooms, but appeared restricted in its geographic distribution. The relationship between Microcystis ITS population structure and abiotic variables (water clarity, pH) and with zooplankton (Daphnia biomass) indicates a (limited) influence of environmental conditions on Microcystis population structure in the reservoirs of Tigray.     

Individual Microcystis colonies harbour distinct bacterial communities that differ by Microcystis oligotype and with time

Interactions between bacteria and phytoplankton in the phycosphere have impacts at the scale of whole ecosystems, including the development of harmful algal blooms. The cyanobacterium Microcystis causes toxic blooms that threaten freshwater ecosystems and human health globally. Microcystis grows in colonies that harbour dense assemblages of other bacteria, yet the taxonomic composition of these phycosphere communities and the nature of their interactions with Microcystis are not well characterized. To identify the taxa and compositional variance within Microcystis phycosphere communities, we performed 16S rRNA V4 region amplicon sequencing on individual Microcystis colonies collected biweekly via high-throughput droplet encapsulation during a western Lake Erie cyanobacterial bloom. The Microcystis phycosphere communities were distinct from microbial communities in whole water and bulk phytoplankton seston in western Lake Erie but lacked ‘core’ taxa found across all colonies. However, dissimilarity in phycosphere community composition correlated with sampling date and the Microcystis 16S rRNA oligotype. Several taxa in the phycosphere were specific to and conserved with Microcystis of a single oligotype or sampling date. Together, this suggests that physiological differences between Microcystis strains, temporal changes in strain phenotypes, and the composition of seeding communities may impact community composition of the Microcystis phycosphere.     

Widespread formation of intracellular calcium carbonates by the bloom-forming cyanobacterium Microcystis

The formation of intracellular amorphous calcium carbonates (iACC) has been recently observed in a few cultured strains of Microcystis, a potentially toxic bloom-forming cyanobacterium found worldwide in freshwater ecosystems. If iACC-forming Microcystis are abundant within blooms, they may represent a significant amount of particulate Ca. Here, we investigate the significance of iACC biomineralization by Microcystis. First, the presence of iACC-forming Microcystis cells has been detected in several eutrophic lakes, indicating that this phenomenon occurs under environmental conditions. Second, some genotypic (presence/absence of ccyA, a marker gene of iACC biomineralization) and phenotypic (presence/absence of iACC) diversity have been detected within a collection of strains isolated from one single lake. This illustrates that this trait is frequent but also variable within Microcystis even at a single locality. Finally, one-third of publicly available genomes of Microcystis were shown to contain the ccyA gene, revealing a wide geographic and phylogenetic distribution within the genus. Overall, the present work shows that the formation of iACC by Microcystis is common under environmental conditions. While its biological function remains undetermined, this process should be further considered regarding the biology of Microcystis and implications on the Ca geochemical cycle in freshwater environments.     

Detection of potential microcystin-producing cyanobacteria in Brazilian reservoirs with a mcyB molecular marker

One of the most serious problems related to water eutrophication is the occurrence of increasingly frequent blooms of toxic cyanobacteria in freshwater ecosystems. Microcystin (MCYST) molecular markers may be used for the detection of toxic cyanobacteria, both cultivated strains and environmental samples, independently of their taxonomic category and production of the toxin at the moment of analysis. Sixty Microcystis spp. strains from 15 water reservoirs of south, southeastern and northeastern Brazil were analyzed by polymerase chain reaction (PCR) with oligonucleotide primers for mcyB gene of the operon that encodes a microcystin synthetase. It was found out that the presence of a unique amplified product of approximately 780 bp in 18 strains, indicated the presence of the microcystin-producing genotype. There was correspondence between the presence of the mcyB gene and microcystin determined by ELISA. Eight reservoirs contained toxic strains, two of these reservoirs being used mainly for public water supply. The coexistence of a mixture of toxic and non-toxic genotypes in populations of several reservoirs was found. Thus, it is evident that Microcystis populations present in blooms compose a mosaic, with genetically different individuals within the same population, each one, possibly, with its own tolerance to environmental factors and with distinct toxicity potential.     

Strong effects of amoebae grazing on the biomass and genetic structure of a Microcystis bloom (Cyanobacteria)

Despite its importance for bloom toxicity, the factors determining the population structure of cyanobacterial blooms are poorly understood. Here, we report the results of a two‐year field survey of the population dynamics of Microcystis blooms in a small hypertrophic urban pond. Microscopic enumeration of Microcystis and its predators and parasites was combined with pigment and microcystin analysis and denaturing gradient gel electrophoresis of the ITS rDNA region to assess population dynamics and structure. Two main Microcystis morpho‐ and ITS types were revealed, corresponding to M. aeruginosa and M. viridis. In both years, high population densities of naked amoebae grazing on Microcystis coincided with rapid decreases in Microcystis biomass. In one year, there was a shift from heavily infested M. aeruginosa to the less‐infested M. viridis, allowing the bloom to rapidly recover. The preference of amoebae for M. aeruginosa was confirmed by grazing experiments, in which several amoeba strains were capable of grazing down a strain of M. aeruginosa, but not of M. viridis. Zooplankton and chytrid parasites appeared to be of minor importance for these strong and fast reductions in Microcystis biomass. These findings demonstrate a strong impact of small protozoan grazers on the biomass and genetic structure of Microcystis blooms.     

Toxicity to Daphnia of a compound extracted from laboratory and natural Microcystis spp., and the role of microcystins

1. The microcystin content of a variety of Microcystis spp., from both laboratory strains and natural blooms, was analysed by HPLC. The microcystin content of laboratory strains ranged from 1.6 to 4.3μgmg^?1 dry weight. Yearly and seasonal variation was detected in an analysis of bloom material collected from Bautzen Reservoir over a 3-year period. The microcystin concentration in bloom material ranged from undetectable to 1.16 μg ml^?1 dry weight. 2. Toxicity of laboratory and natural Microcystis to Daphnia pulicaria was determined using an established LC₅₀ technique. Partially purified water extracts from different Microcystis samples exhibited a wide range of toxicity. The highest activity was found in natural Microcystis samples, with an LC₅₀ of 36 μgm^?1 dry weight of Microcystis, whereas one strain did not appear toxic at 1600 μg ml^?1. 3. No correlation was found between the concentrations of microcystins of different laboratory and natural Microcystis strains and the toxicity of extracts to Daphnia pulicaria from the same strains. Therefore, we discriminated between hepatotoxic microcystins and the compound(s) that is toxic to Daphnia, here termed DTC (Daphnia-toxic compound), which is independent of microcystins.     

Intraspecific trait variation and trade‐offs within and across populations of a toxic dinoflagellate

Intraspecific trait diversity can promote the success of a species, as complementarity of functional traits within populations may enhance its competitive success and facilitates resilience to changing environmental conditions. Here, we experimentally determined the variation and relationships between traits in 15 strains of the toxic dinoflagellate Alexandrium ostenfeldii derived from two populations. Measured traits included growth rate, cell size, elemental composition, nitrogen uptake kinetics, toxin production and allelochemical potency. Our results demonstrate substantial variation in all analysed traits both within and across populations, particularly in nitrogen affinity, which was even comparable to interspecific variation across phytoplankton species. We found distinct trade‐offs between maximum nitrogen uptake rate and affinity, and between defensive and competitive traits. Furthermore, we identified differences in trait variation between the genetically similar populations. The observed high trait variation may facilitate development and resilience of harmful algal blooms under dynamic environmental conditions.     

Impacts of a Toxic <Emphasis Type="Italic">Microcystis</Emphasis> Bloom on the Macroinvertebrate Fauna of Lake Elphinstone,Central Queensland,Australia

The biological, physical and chemical properties of Lake Elphinstone were studied during a dense, toxic cyanoprokaryote bloom dominated by Microcystis. Decreases in total abundance and richness in macroinvertebrate communities coincided with increases in Microcystis toxicity. Water quality was characterized by high light attenuation values caused by abiogenic turbidity and shading and absorbance from thick algal scums. The study highlights the potential for multidimensional environmental impacts associated with toxic cyanoprokaryote blooms, and the consequent implications for the management of shallow, inland and tropical lakes that are susceptible to toxic blooms.     

Functional significance of phylogeographic structure in a toxic benthic marine microbial eukaryote over a latitudinal gradient along the East Australian Current

Genetic diversity in marine microbial eukaryotic populations (protists) drives their ecological success by enabling diverse phenotypes to respond rapidly to changing environmental conditions. Despite enormous population sizes and lack of barriers to gene flow, genetic differentiation that is associated with geographic distance, currents, and environmental gradients has been reported from planktonic protists. However, for benthic protists, which have reduced dispersal opportunities, phylogeography and its phenotypic significance are little known. In recent years, the East Australian Current (EAC) has intensified its southward flow, associated with the tropicalization of temperate waters. Benthic harmful algal species have been increasingly found in south‐eastern Australia. Yet little is known about the potential of these species to adapt or extend their range in relation to changing conditions. Here, we examine genetic diversity and functional niche divergence in a toxic benthic dinoflagellate, Ostreopsis cf. siamensis, along a 1,500 km north–south gradient in southeastern Australia. Sixty‐eight strains were established from eight sampling sites. The study revealed long‐standing genetic diversity among strains established from the northern‐most sites, along with large phenotypic variation in observed physiological traits such as growth rates, cell volume, production of palytoxin‐like compounds, and photophysiological parameters. Strains from the southern populations were more uniform in both genetic and functional traits, and have possibly colonized their habitats more recently. Our study reports significant genetic and functional trait variability in a benthic harmful algal species, indicative of high adaptability, and a possible climate‐driven range extension. The observed high trait variation may facilitate development of harmful algal blooms under dynamic coastal environmental conditions.     

Colony formation in the cyanobacterium Microcystis

Morphological evolution from a unicellular to multicellular state provides greater opportunities for organisms to attain larger and more complex living forms. As the most common freshwater cyanobacterial genus, Microcystis is a unicellular microorganism, with high phenotypic plasticity, which forms colonies and blooms in lakes and reservoirs worldwide. We conducted a systematic review of field studies from the 1990s to 2017 where Microcystis was dominant. Microcystis was detected as the dominant genus in waterbodies from temperate to subtropical and tropical zones. Unicellular Microcystis spp. can be induced to form colonies by adjusting biotic and abiotic factors in laboratory. Colony formation by cell division has been induced by zooplankton filtrate, high Pb²⁺ concentration, the presence of another cyanobacterium (Cylindrospermopsis raciborskii), heterotrophic bacteria, and by low temperature and light intensity. Colony formation by cell adhesion can be induced by zooplankton grazing, high Ca²⁺ concentration, and microcystins. We hypothesise that single cells of all Microcystis morphospecies initially form colonies with a similar morphology to those found in the early spring. These colonies gradually change their morphology to that of M. ichthyoblabe, M. wesenbergii and M. aeruginosa with changing environmental conditions. Colony formation provides Microcystis with many ecological advantages, including adaption to varying light, sustained growth under poor nutrient supply, protection from chemical stressors and protection from grazing. These benefits represent passive tactics responding to environmental stress. Microcystis colonies form at the cost of decreased specific growth rates compared with a unicellular habit. Large colony size allows Microcystis to attain rapid floating velocities (maximum recorded for a single colony, ∼ 10.08 m h⁻¹) that enable them to develop and maintain a large biomass near the surface of eutrophic lakes, where they may shade and inhibit the growth of less‐buoyant species in deeper layers. Over time, accompanying species may fail to maintain viable populations, allowing Microcystis to dominate. Microcystis blooms can be controlled by artificial mixing. Microcystis colonies and non‐buoyant phytoplankton will be exposed to identical light conditions if they are evenly distributed over the water column. In that case, green algae and diatoms, which generally have a higher growth rate than Microcystis, will be more successful. Under such mixing conditions, other phytoplankton taxa could recover and the dominance of Microcystis would be reduced. This review advances our understanding of the factors and mechanisms affecting Microcystis colony formation and size in the field and laboratory through synthesis of current knowledge. The main transition pathways of morphological changes in Microcystis provide an example of the phenotypic plasticity of organisms during morphological evolution from a unicellular to multicellular state. We emphasise that the mechanisms and factors influencing competition among various close morphospecies are sometimes paradoxical because these morphospecies are potentially a single species. Further work is required to clarify the colony‐forming process in different Microcystis morphospecies and the seasonal variation in this process. This will allow researchers to grow laboratory cultures that more closely reflect field morphologies and to optimise artificial mixing to manage blooms more effectively.     

Response of bacterial communities to cyanobacterial harmful algal blooms in Lake Taihu,China

Cyanobacterial harmful algal blooms are prevalent around the world, influencing aquatic organisms and altering the physico-chemical properties in freshwater systems. However, the response of bacterial communities to toxic cyanobacterial blooms and associated microcystins (MC) remain poorly understood even though global concentrations of MC have increased dramatically in the past few decades. To address this issue, the dynamics of bacterial community composition (BCC) in the water column and how BCC is influenced by both harmful cyanobacterial blooms and environmental factors were investigated on a monthly basis from August 2013 to July 2014 in Lake Taihu, China. Non-metric multidimensional scaling (NMDS) revealed that seasonal variation in BCC was significant, and that the succession of BCC greatly depends on changes in environmental conditions. Redundancy analysis (RDA) results showed that the overall variation of BCC was explained mainly by dissolved oxygen (DO), nitrate nitrogen (NO₃⁻-N), and Microcystis. The alpha biodiversity of the bacterial community was different among months with the highest diversity in February and the lowest diversity in October. Furthermore, significant negative relationships were found between alpha biodiversity indices and Microcystis abundance as well as with intracellular MC concentrations, indicating that Microcystis and associated MC may influence the bacterial community structure by reducing its biodiversity. This study shows that potential associations exist between toxic cyanobacterial blooms and bacterial communities but more investigations are needed to obtain a mechanistic understanding of their complex relationships.     

Maternal consumption of non‐toxic Microcystis by Daphnia magna induces tolerance to toxic Microcystis in offspring

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广东省水库微囊藻的产毒特征和ITS序列的遗传多样性分析

为了解广东省水库微囊藻的产毒特征和ITS 序列的遗传多样性,从广东省供水水库中分离得到28 株微囊藻(Microcystisspp.),对它们的产毒特征和15 株微囊藻的ITS 序列进行了分析.高效液相色谱(HPLC)和微囊藻毒素合成酶基因mcyE 的检测结果表明,广东省水库中的微囊藻以产毒藻株占优势,微囊藻毒素的主要类型为MC-RR.广东省15 株藻株的ITS 序列相似性大于93.2%,在用相邻法(NJ)构建的系统树上,不同形态的种和不同地理区域的藻株没有区分开,产毒和非产毒藻株没有形成独立分支.这说明微囊藻ITS 序列的遗传多样性较低,ITS 序列和mcyE 存在没有相关性,表型不能够反映藻株的进化关系.因此,有必要将藻类传统分类方法与分子方法结合起来对蓝藻进行重新分类.     

Geographical variation in rotifers associated with Microcystis blooms

Lake George, Uganda, lies on the equator and shows little variation in temperature or in the dominance of Microcystis in the phytoplankton. The dominant planktonic rotifers in Lake George are compared to those found in lakes in other parts of the world, ranging from tropical and subtropical lakes with semi-permanent blooms of Microcystis to temperate localities with summer blooms or less regular blooms at multiannual intervals. A modified Sorensen Similarity Index is used to show a latitudinal gradient in the rotifers associated with Microcystis.     

Quantification of toxigenic Microcystis spp. in freshwaters by quantitative real-time PCR based on the microcystin synthetase A gene

A method to estimate the abundance of toxigenic Microcystis in environmental samples by using quantitative real-time PCR was developed and optimized. The basis of this method is the amplification of a highly conserved region of the mcyA gene within the microcystin synthetase gene cluster. Using this method, the average copy number of mcyA gene per cell in toxigenic Microcystis strains was estimated. The molecular markers and method developed in this study can be used to monitor toxigenic strains of Microcystis in Korean freshwaters, in which harmful cyanobacterial blooms are routinely found.     

Low levels of quantitative and molecular genetic differentiation among natural populations of Medicago ciliaris Kroch. (Fabaceae) of different Tunisian eco-geographical origin

In this paper, we analyze the genetic variability in four Tunisian natural populations of Medicago ciliaris using 19 quantitative traits and six polymorphic microsatellite loci. We investigated the amplification transferability of 30 microsatellites developed in the model legume M. truncatula to M. ciliaris. Results revealed that about 56.66% of analyzed markers are valuable genetic markers for M. ciliaris. The most genetic diversity at quantitative traits and microsatellite loci was found to occur within populations (>80%). Low differentiations among populations at quantitative traits Q _ST  = 0.146 and molecular markers F _ST  = 0.18 were found. The majority of measured traits exhibited no significant difference in the level of Q _ST and F _ST . Furthermore, significant correlations established between these traits and eco-geographical factors suggested that natural selection should be invoked to explain the level of phenotypic divergence among populations rather than drift. There was no significant correlation between population differentiation at quantitative traits and molecular markers. Significant spatial genetic structure consistent with models of isolation by distance was detected within all studied populations. The site-of-origin environmental factors explain about 9.07% of total phenotypic genetic variation among populations. The eco-geographical factors that influence more the variation of measured traits among populations are the soil texture and altitude. Nevertheless, there were no consistent pattern of associations between gene diversity (He) and environmental factors.     

Natural quantitative genetic variance in plant growth differs in response to ecologically relevant temperature heterogeneity

Adaptation to large‐scale spatial heterogeneity in the environment accounts for a major proportion of genetic diversity within species. Theory predicts the erosion of adaptive genetic variation on a within‐population level, but considerable genetic diversity is often found locally. Genetic diversity could be expected to be maintained within populations in temporally or spatially variable conditions if genotypic rank orders vary across contrasting microenvironmental settings. Taking advantage of fine‐resolution environmental data, we tested the hypothesis that temperature heterogeneity among years could be one factor maintaining quantitative genetic diversity within a natural and genetically diverse plant population. We sampled maternal families of Boechera stricta, an Arabidopsis thaliana relative, at one location in the central Rocky Mountains and grew them in three treatments that, based on records from an adjacent weather station, simulated hourly temperature changes at the native site during three summers with differing mean temperatures. Treatment had a significant effect on all traits, with 2–3‐fold increase in above‐ and belowground biomass and the highest allocation to roots observed in the treatment simulating the warmest summer on record at the site. Treatment affected bivariate associations between traits, with the weakest correlation between above‐ and belowground biomass in the warmest treatment. The magnitude of quantitative genetic variation for all traits differed across treatments: Genetic variance of biomass was 0 in the warmest treatment, while highly significant diversity was found in average conditions, resulting in broad‐sense heritability of 0.31. Significant genotype × environment interactions across all treatments were found only in root‐to‐shoot ratio. Therefore, temperature variation among summers appears unlikely to account for the observed levels of local genetic variation in size in this perennial species, but may influence family rank order in growth allocation. Our results indicate that natural environmental fluctuations can have a large impact on the magnitude of within‐population quantitative genetic variance.     

Genetic Diversity： Geographical Distribution and Toxin Profiles of Microcystis Strains （Cyanobacteria） in China

Twenty strains of Microcystis Kütz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of cpcBA-IGS nucleotlde sequence, the derived neighbor-joining （NJ） and maximum parsimony （MP） trees Indicate that these strains of Microcystis can be divided into four clusters. The strains from south, middle and north region of China formed distinct lineages, suggesting high diversity and a geographical distribution from south to north locations. Moreover, the results being indicating high variable genotypes of the strains of the Microcystis strains from the same lake show that there Is high diversity of Microcystis within a water bloom population. Comparing the results of the present study with those reported for compared with 43 strains of Microcystis from other locations, also reveals Chinese strains have high similarity with those from regions in the North Hemispherical. This suggests that the Microcystis strains In the world might have a geographical distribution. Analysis of 30 strains using the primers MCF/TER and TOX2P/TOX2M showed that there was no correlation between the gene of cpcBA-IGS and the presence of racy. Toxic strains were founded to be predominant in different water bodies throughout China.     

The effects of temperature and nutrients on the growth and dynamics of toxic and non-toxic strains of Microcystis during cyanobacteria blooms

In temperate latitudes, toxic cyanobacteria blooms often occur in eutrophied ecosystems during warm months. Many common bloom-forming cyanobacteria have toxic and non-toxic strains which co-occur and are visually indistinguishable but can be quantified molecularly. Toxic Microcystis cells possess a suite of microcystin synthesis genes (mcyA–mcyJ), while non-toxic strains do not. For this study, we assessed the temporal dynamics of toxic and non-toxic strains of Microcystis by quantifying the microcystin synthetase gene (mcyD) and the small subunit ribosomal RNA gene, 16S (an indicator of total Microcystis), from samples collected from four lakes across the Northeast US over a two-year period. Nutrient concentrations and water quality were measured and experiments were conducted which examined the effects of elevated levels of temperatures (+4 °C), nitrogen, and phosphorus on the growth rates of toxic and non-toxic strains of Microcystis. During the study, toxic Microcystis cells comprised between 12% and 100% of the total Microcystis population in Lake Ronkonkoma, NY, and between 0.01% and 6% in three other systems. In all lakes, molecular quantification of toxic (mcyD-possessing) Microcystis was a better predictor of in situ microcystin levels than total cyanobacteria, total Microcystis, chlorophyll a, or other factors, being significantly correlated with the toxin in every lake studied. Experimentally enhanced temperatures yielded significantly increased growth rates of toxic Microcystis in 83% of experiments conducted, but did so for non-toxic Microcystis in only 33% of experiments, suggesting that elevated temperatures yield more toxic Microcystis cells and/or cells with more mcyD copies per cell, with either scenario potentially yielding more toxic blooms. Furthermore, concurrent increases in temperature and P concentrations yielded the highest growth rates of toxic Microcystis cells in most experiments suggesting that future eutrophication and climatic warming may additively promote the growth of toxic, rather than non-toxic, populations of Microcystis, leading to blooms with higher microcystin content.     

Daphnia and Toxic Blooms of Microcystis aeruginosa in Bautzen Reservoir (GDR)

As a part of a whole-lake, long-term experiment in biomanipulation in. the hypertrophic Bautzen reservoir (G.D.R.), during three years (1984–1986) the dynamics of mouse-related LD 50 of Microcystis aeruginosa was compared with the biomass development of this blue-green and the grazing pressure exerted by Daphnia galeata. Since the three summer averages of the biomass of D. galeata revealed strong differences due to decreasing predation activity of fish from 1984 to 1986, the effects of different grazing pressure on Microcystis toxicity could be investigated under field conditions. Microcystis was nontoxic at the beginning of the growing season and developed high toxicity during its first strong biomass increase in summer in all three years. But this decrease of the LD 50 together with the first biomass increase of the season is found in quite different periods in different years (1984: August, 1985: July, 1986: June). It is obvious that the higher the mean effective filtration rate of D. galeata during summer is found the faster the toxicity of Microcystis is formed. If these observations are combined with findings of other authors, the conclusion can be drawn that the development of toxic Microcystis blooms seems to be promoted by a combination of five conditions: (1) Presence of a mixture of toxic and nontoxic Microcystis strains at the beginning of the growing season even if the portion of toxic strains is very low, (2) physical and chemical growth conditions which favour Microcystis over other phytoplankton, (3) high grazing pressure by zooplankton on edible food particles over a rather long period, (4) patchy distribution of the different Microcystis strains if nonselective filtrators such as Daphnia dominate the zooplankton, and (5) absence of defense mechanisms of Microcystis against grazing which are not coupled with toxicity (e.g. large colony size). These conclusions contribute to a better understanding of the possibilities and limits of in-lake eutrophication control by biomanipulation and emphasize the need to combine top-down and bottom-up control mechanisms in eutrophic and hypertrophic waters.