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PubMed2004

Sexual selection on morphological and physiological traits and fluctuating asymmetry in the black scavenger fly Sepsis cynipsea.

Previous univariate studies of the fly Sepsis cynipsea (Diptera: Sepsidae) have demonstrated spatiotemporally variable and consequently overall weak sexual selection favouring large male size, which is nevertheless stronger on average than fecundity selection favouring larger females. To identify specific target(s) of selection on body size and additional traits possibly affecting mating success, two multivariate field studies of sexual selection were conducted. In one study using seasonal replicates from three populations, we assessed 15 morphological traits. No clear targets of sexual selection on male size could be detected, perhaps because spatiotemporal variation in selection was again strong. In particular, there was no (current) selection on male abdomen length or fore coxa length, the only traits for which S. cynipsea males are not smaller than females. Interestingly, copulating males had a consistently shorter fore femur base, a secondary sexual trait, and a wider clasper (hypopygium) gap, an external genital trait. In a second study using daily and seasonal replicates from one population, we included physiological measures of energy reserves (lipids, glucose, glycogen), in addition to hind tibia length and fluctuating asymmetry (FA) of all pairs of legs. This study again confirmed the mating advantage of large males, and additionally suggests independent positive influences of lipids (the long-term energy stores), with effects of glucose and glycogen (the short-term energy stores) tending to be negative. FA of paired traits was not associated with male mating success. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection, which is rare, would be fruitful in other species.

Animals↗

PubMed2006

Conservation of species in dynamic landscapes: divergent fates of Silene tatarica populations in riparian habitats.

In transient environments, where local extinctions occur as a result of destruction or deterioration of the local habitat, the long-term persistence of a species requires successful colonizations at new, suitable sites. This kind of habitat tracking should be associated with the asynchronous dynamics of local populations, and it can be especially important for the conservation of rare plant species in riparian habitats. We determined spatiotemporal variation in the demography of the perennial Silene tatarica (L.) Pers. in 15 populations (1998-2003) located in periodically disturbed riparian habitats. The habitats differed according to their morphology (flat shores, slopes) and the amount of bare ground (open, intermediate, closed) along a successional gradient. We used elasticity and life-table response analyses and stochastic simulations to study the variation in population demography. Finite population growth rate was higher in intermediate habitats than in open and closed habitats. In stochastic simulations population size increased in most cases, but four populations were projected to become extinct within 12-70 years. The viability of local populations depended most on the survival and growth of juvenile individuals and on the fecundity of large fertile individuals. On a regional scale, the persistence of this species will require a viable network of local populations as protection against local extinctions caused by natural disturbances and succession. Accordingly, the long-term persistence of riparian species may depend on habitat changes; thus, their conservation requires maintenance of natural disturbance dynamics. Along regulated rivers, management activities such as the creation of open habitats for new colonization should be implemented. Similarly, these activities can be rather general requirements for the conservation of endangered species dependent on transient habitats along successional gradients.

Computer Simulation↗

PubMed1998

Neonatal vitamin K administration and childhood cancer in the north of England: retrospective case-control study.

OBJECTIVE: To explore the possible association between intramuscular vitamin K given to neonates and the subsequent development of childhood cancer. DESIGN: Retrospective case-control study on the basis of hospital records. SETTING: The former Northern Health region of England. SUBJECTS: 685 children who were born and lived in the region and who developed cancer before their 15th birthday, and 3442 controls also born between 1960 and 1991 and matched only for date and hospital of birth. The notes of a further 701 index cases were untraceable. MAIN EXPOSURE MEASURE: Administration of intramuscular vitamin K versus no exposure to vitamin K. RESULTS: There was no association between the administration of vitamin K and the development of all childhood cancers (unadjusted odds ratio 0.89; 95% confidence interval 0.69 to 1.15) or for all acute lymphoblastic leukaemia (1.20; 0.75 to 1.92), but there was a raised odds ratio for acute lymphoblastic leukaemia developing 1-6 years after birth (1.79; 1.02 to 3.15). No such association was seen in a separate cohort-based study not dependent on case note retrieval in which the rates of acute lymphoblastic leukaemia in children born in hospital units where all babies received vitamin K were compared with those born in units where less than a third received prophylaxis. CONCLUSIONS: It is not possible, on the basis of currently published evidence, to refute the suggestion that neonatal intramuscular vitamin K administration increases the risk of early childhood leukaemia. Any association may have been masked in earlier studies that did not use controls matched for time and locality by other unidentified factors affecting the spatiotemporal variations in incidence of leukaemia.

Adolescent↗

PubMed2001

The expression of ccn3 (nov) RNA and protein in the rat central nervous system is developmentally regulated.

AIMS: To establish the expression pattern of ccn3 (nov) in the central nervous system (CNS) of adult rats and to determine whether spatiotemporal variations in the expression of ccn3 (nov) are related to specific developmental stages and/or specific CNS functions. METHODS: The sites of ccn3 (nov) expression have been identified by in situ hybridisation using didoxigenin labelled cRNA and by the reverse transcription-polymerase chain reaction (RT-PCR). The rat CCN3 (NOV) protein was characterised by western blotting performed on brain extracts. The localisation of the CCN3 (NOV) protein in the brain was established by immunocytochemistry. RESULTS: Increased expression of ccn3 (nov) was detected in the developing brain of rats after birth, as shown by RT-PCR and immunocytochemistry analysis performed on a series of samples taken between day 5 (P5) and day 300 (P300), with a pronounced peak between P15 and P150, suggesting that CCN3 (NOV) might play a role in the maintenance or establishment of specific brain functions. The relatively high amounts of an N-terminal truncated CCN3 (NOV) related protein detected both in the brain tissues and cerebrospinal fluid suggested that post translational processing of CCN3 (NOV) might be particularly prevalent in the brain. Such processing might be of biological importance in the light of the previously reported growth stimulatory effects of N-terminal truncated CCN3 (NOV) isoforms. CONCLUSIONS: The postnatal differential expression of ccn3 (nov) in the brain of developing rats suggests that CCN3 (NOV) might be involved in the acquisition of specific functions. The rat species provides an as yet unequalled system for these studies. Because the CCN3 (NOV) protein is detected in restricted areas of the brain, it will be interesting to establish whether variations of ccn3 (nov) expression are associated with normal cognitive processes and whether ccn3 (nov) expression is affected by aging. In addition, because CCN3 (NOV) is found in the spinal cord and along the axonal processes, it will be of interest to determine the expression of the normal and truncated isoforms of CCN3 (NOV) in various pathological conditions, such as neurodegenerative diseases.

Animals↗

PubMedDate not supplied

An animal model of auditory cortex prostheses.

Experiments aimed at rehabilitating deaf and blind patients with cortical prostheses were first conducted decades ago, but epicortical electrodes allowed only crude information transfer. Here we report that in Mongolian gerbils with electrodes implanted in input layers of the primary auditory cortex, spatial, temporal and spatiotemporal variations in intracortical stimulation all lead to perceptual differences as evidenced by discrimination training. For some stimulus regimes discrimination learning was as fast as with intracochlear stimulation in this animal. Intracortical stimulation induced field potentials and 2-deoxyglucose labeling patterns in primary auditory cortex similar to those induced by auditory click or tone stimuli, respectively. Given the common organization principles of neocortical areas, these results are presumably also of significance to prostheses interfacing with visual cortex.

Animals↗

PubMed1993

Spiral waves of excitation underlie reentrant activity in isolated cardiac muscle.

The mechanism of reentrant ventricular tachycardia was studied in computer simulations and in thin (approximately 20 x 20 x 0.5-mm) slices of dog and sheep ventricular epicardial muscle. A two-dimensional matrix consisting of 96 x 96 electrically coupled cells modeled by the FitzHugh-Nagumo equations was used to analyze the dynamics of self-sustaining reentrant activity in the form of elliptical spiral waves induced by premature stimulation. In homogeneous anisotropic media, spirals are stationary and may last indefinitely. However, the presence of small parameter gradients may lead to drifting and eventual termination of the spiral at the boundary of the medium. On the other hand, spirals may anchor and rotate around small discontinuities within the matrix. Similar results were obtained experimentally in 10 preparations whose electrical activity was monitored by means of a potentiometric dye and high-resolution optical mapping techniques; premature stimulation triggered reproducible episodes of sustained or nonsustained reentrant tachycardia in the form of spiral waves. As a rule, the spirals were elongated, with the major hemiaxis parallel to the longitudinal axis of the cells. The period of rotation (183 +/- 68 msec [mean +/- SD]) was longer than the refractory period (131 +/- 38 msec) and appeared to be determined by the size of the spiral's core, which was measured using a newly devised "frame-stack" plot. Drifting of spiral waves was also observed experimentally. Drift velocity was 9.8% of the velocity of wave propagation. In some cases, the core became stationary by anchoring to small arteries or other heterogeneities, and the spiral rotated rhythmically for prolonged periods of time. Yet, when drift occurred, spatiotemporal variations in the excitation period were manifested as a result of a Doppler effect, with the excitation period ahead of the core being 20 +/- 6% shorter than the excitation period behind the core. As a result of these coexisting frequencies, a pseudoelectrocardiogram of the activity in the presence of a drifting spiral wave exhibited "QRS complexes" with an undulating axis, which resembled those observed in patients with torsade de pointes. The overall results show that spiral wave activity is a property of cardiac muscle and suggest that such activity may be the common mechanism of a number of monomorphic and polymorphic tachycardias.

Animals↗

PubMed2000

Dynamics of strongly-coupled spiking neurons.

We present a dynamical theory of integrate-and-fire neurons with strong synaptic coupling. We show how phase-locked states that are stable in the weak coupling regime can destabilize as the coupling is increased, leading to states characterized by spatiotemporal variations in the interspike intervals (ISIs). The dynamics is compared with that of a corresponding network of analog neurons in which the outputs of the neurons are taken to be mean firing rates. A fundamental result is that for slow interactions, there is good agreement between the two models (on an appropriately defined timescale). Various examples of desynchronization in the strong coupling regime are presented. First, a globally coupled network of identical neurons with strong inhibitory coupling is shown to exhibit oscillator death in which some of the neurons suppress the activity of others. However, the stability of the synchronous state persists for very large networks and fast synapses. Second, an asymmetric network with a mixture of excitation and inhibition is shown to exhibit periodic bursting patterns. Finally, a one-dimensional network of neurons with long-range interactions is shown to desynchronize to a state with a spatially periodic pattern of mean firing rates across the network. This is modulated by deterministic fluctuations of the instantaneous firing rate whose size is an increasing function of the speed of synaptic response.

Animals↗

PubMed2001

Three different calcium wave pacemakers in ascidian eggs.

Calcium wave pacemakers in fertilized eggs of ascidians and mouse are associated with accumulations of cortical endoplasmic reticulum in the vegetal hemisphere. In ascidians, two distinct pacemakers (PM1 and PM2) generate two series of calcium waves necessary to drive meiosis I and II. Pacemaker PM2 is stably localized in a cortical ER accumulation situated in the vegetal contraction pole. We now find that pacemaker PM1 is situated in a cortical ER-rich domain that forms around the sperm aster and moves with it during the calcium-dependant cortical contraction triggered by the fertilizing sperm. Global elevations of inositol (1,4,5)-trisphosphate (Ins(1,4,5)P3) levels produced by caged Ins(1,4,5)P3 or caged glycero-myo-PtdIns(4,5)P2 photolysis reveal that the cortex of the animal hemisphere, also rich in ER-clusters, is the cellular region most sensitive to Ins(1,4,5)P3 and acts as a third type of pacemaker (PM3). Surprisingly, the artificial pacemaker PM3 predominates over the natural pacemaker PM2, located at the opposite pole. Microtubule depolymerization does not alter the activity nor the location of the three pacemakers. By contrast, blocking the acto-myosin driven cortical contraction with cytochalasin B prevents PM1 migration and inhibits PM2 activity. PM3, however, is insensitive to cytochalasin B. Our experiments suggest that the three distinct calcium wave pacemakers are probably regulated by different spatiotemporal variations in Ins(1,4,5)P3 concentration. In particular, the activity of the natural calcium wave pacemakers PM1 and PM2 depends on the apposition of a cortical ER-rich domain to a source of Ins(1,4,5)P3 production in the cortex. Movies available on-line

Actins↗

PubMed2006

The influence of hitchhiking and deleterious mutation upon asexual mutation rates.

The question of how natural selection affects asexual mutation rates has been considered since the 1930s, yet our understanding continues to deepen. The distribution of mutation rates observed in natural bacteria remains unexplained. It is well known that environmental constancy can favor minimal mutation rates. In contrast, environmental fluctuation (e.g., at period T) can create indirect selective pressure for stronger mutators: genes modifying mutation rate may "hitchhike" to greater frequency along with environmentally favored mutations they produce. This article extends a well-known model of Leigh to consider fitness genes with multiple mutable sites (call the number of such sites alpha). The phenotypic effect of such a gene is enabled if all sites are in a certain state and disabled otherwise. The effects of multiple deleterious loci are also included (call the number of such loci gamma). The analysis calculates the indirect selective effects experienced by a gene inducing various mutation rates for given values of alpha, gamma, and T. Finite-population simulations validate these results and let us examine the interaction of drift with hitchhiking selection. We close by commenting on the importance of other factors, such as spatiotemporal variation, and on the origin of variation in mutation rates.

Models, Genetic↗

PubMed2007

Assessment of water quality and identification of pollution sources of plateau lakes in Yunnan (China).

The plateau lakes of Yunnan are important both ecologically and economically in China. Nevertheless, the human impact on water quality in these lakes has become increasingly highlighted. The water quality of 10 plateau lakes was monitored regularly over the period of 2000 through 2004 for 24 parameters. Multivariate statistical techniques, including cluster analysis (CA), factor analysis (FA), and principal component analysis (PCA), were employed to better interpret information about the water quality and its pollution sources. No obvious data reduction from CA/FA was found because three principal components (PCs) needed 14 variables to explain 85.01% of the total variance. However, three latent factors accounted for pollution mainly from the following sources: agricultural activities, residential activities and anthropogenic-toxic pollution from industrial effluents, or other special activities. Box-whiskers plots were employed to visually interpret the spatiotemporal variations of water quality variables, which were highly correlated with three PCs. Three types of water quality (i.e., low-, medium-, and high-polluted lakes) were determined through CA based on the similarity of water quality variables. Our results may provide helpful information for the authorities to effectively manage the water quality and make sound policies.

China↗

PubMed1992

Myosin heavy chain expression in rabbit masseter muscle during postnatal development.

The expression of isoforms of myosin heavy chain (MHC) during postnatal development was studied in the masseter muscle of the rabbit. Evidence is presented that in addition to adult fast and slow myosin, the rabbit masseter contains neonatal and 'cardiac' alpha-MHC. During postnatal growth myosin transitions take place from neonatal and fast (IIA, IIA/IIB--referring to a fibre containing both IIA and IIB MHCs) MHC to adult 'cardiac' alpha-MHC and I/alpha-MHC. Since there is a temporary population of fibres containing IIA/alpha-MHC during the first 4 wk of development with a peak in the 3rd to 4th wk, the transition from IIA-MHC to alpha-MHC may occur in these IIA/alpha-MHC-containing fibres. The appearance of 'cardiac' alpha-MHC coincides with the timing of weaning, suggesting that the changes in MHC content, that probably result in a transition to a lower speed of contraction, have functional significance related to weaning. The finding of neonatal MHC in adult rabbits indicates that the masseter develops at a rate and in a way that is distinct from most other skeletal muscles. A spatiotemporal variation in expression of myosin isozymes within the masseter was observed, with many fibres containing more than one myosin type, indicating developmentally regulated spatial differences in function.

Adenosine Triphosphatases↗

PubMed1998

Multitasking in the olfactory system: context-dependent responses to odors reveal dual GABA-regulated coding mechanisms in single olfactory projection neurons.

Studies of olfaction have focused mainly on neural processing of information about the chemistry of odors, but olfactory stimuli have other properties that also affect central responses and thus influence behavior. In moths, continuous and intermittent stimulation with the same odor evokes two distinct flight behaviors, but the neural basis of this differential response is unknown. Here we show that certain projection neurons (PNs) in the primary olfactory center in the brain give context-dependent responses to a specific odor blend, and these responses are shaped in several ways by a bicuculline-sensitive GABA receptor. Pharmacological dissection of PN responses reveals that bicuculline blocks GABAA-type receptors/chloride channels in PNs, and that these receptors play a critical role in shaping the responses of these glomerular output neurons. The firing patterns of PNs are not odor-specific but are strongly modulated by the temporal pattern of the odor stimulus. Brief repetitive odor pulses evoke fast inhibitory potentials, followed by discrete bursts of action potentials that are phase-locked to the pulses. In contrast, the response to a single prolonged stimulus with the same odor is a series of slow oscillations underlying irregular firing. Bicuculline disrupts the timing of both types of responses, suggesting that GABAA-like receptors underlie both coding mechanisms. These results suggest that glomerular output neurons could use more than one coding scheme to represent a single olfactory stimulus. Moreover, these context-dependent odor responses encode information about both the chemical composition and the temporal pattern of the odor signal. Together with behavioral evidence, these findings suggest that context-dependent odor responses evoke different perceptions in the brain that provide the animal with important information about the spatiotemporal variations that occur in natural odor plumes.

Action Potentials↗

PubMed2006

Demography of central and marginal populations of monkeyflowers (Mimulus cardinalis and M. lewisii).

Every species occupies a limited geographic area, but how spatiotemporal environmental variation affects individual and population fitness to create range limits is not well understood. Because range boundaries arise where, on average, populations are more likely to go extinct than to persist, range limits are an inherently population-level problem for which a demographic framework is useful. In this study, I compare demographic parameters and population dynamics between central and marginal populations of monkeyflowers, Mimulus cardinalis and M. lewisii, along an elevation gradient spanning both species' ranges. Central and marginal populations of both species differed in survival and fecundity. For M. lewisii, these components of fitness were higher in central than in marginal populations, but for M. cardinalis the converse was true. To assess spatiotemporal variation in population dynamics, I used transition matrix models to estimate asymptotic population growth rates (lambda) and found that population growth rates of M. lewisii were highest at the range center and reduced at the range margin. Population growth rates of M. cardinalis were highest at the range margin and greatly reduced at the range center. Life table response analysis decomposed spatiotemporal variation in lambda into contributions from each transition between life stages, finding that transitions from large nonreproductive and reproductive plants to the seed class and stasis in the reproductive class made the largest contributions to spatial differences in lambda. These transitions had only low to moderate sensitivities, indicating that differences in projected population growth rates resulted mainly from observed differences in transition matrix parameters and their underlying vital rates.

Altitude↗

PubMed2006

Spatiotemporal structure of genetic variation of a spreading plant metapopulation on dynamic riverbanks along the Meuse River.

Long-distance seed dispersal is a crucial determinant of within-population genetic variability and among-population genetic differentiation in plant metapopulations undergoing recurrent local extinctions and (re-)colonization. We investigated the spatial and temporal structure of genetic variation in a metapopulation of Sisymbrium austriacum located along a dynamic river system using dominant AFLP markers. Data on riverbank dynamics and colonization history allowed separating populations based on their age (< or =5 vs >5 years old). Bayesian analysis of population genetic structure indicated that populations were significantly differentiated from each other, but Mantel tests revealed that there was no relationship between pairwise geographic and genetic distances, suggesting that long-distance seed dispersal partly determines spatial genetic structure. Recent populations were less differentiated from each other than old populations. Analysis of molecular variance (AMOVA) indicated that both spatial factors and population age significantly determined genetic diversity, the effects of age being more important than spatial location. Clustering analysis revealed five large clusters, which were related primarily to population age and to a minor extent to geographical location. Our results indicate that the recurrent formation and destruction of riverbank habitats following peak flow events have a large impact on genetic diversity of riparian plant species.

Belgium↗

PubMed2026

The Charcot-Marie-Tooth Neuropathy (CMTX3) Complex Structural Variation Causes Differential SOX3 Spatiotemporal Expression.

Charcot-Marie-Tooth (CMT) neuropathy is a clinically and genetically heterogeneous group of diseases characterized by the length-dependent axonal degeneration of peripheral nerves. We previously mapped a rare form of X-linked CMT, CMTX3, to a 5.7-Mb interval on chromosome Xq26.3-q27.1 and excluded the coding region of all known genes in the linkage interval for mutations. Whole genome sequencing subsequently identified a 78-kb region of chromosome 8q24.3 that had been duplicated and inserted into the CMTX3 locus between the genes HAPSTR2 and SOX3. The 78-kb insertion, which contains a partial transcript of ARHGAP39, fully segregated in families with CMTX3 and was absent in neurologically normal controls. To retain the CMTX3 insertion and investigate its consequences in appropriate neuronal tissue, we generated induced pluripotent stem cells (iPSCs) from CMTX3 fibroblasts. Using bulk RNA sequencing of patient-derived spinal motor neurons, ARHGAP39 was deemed nonpathogenic by excluding both the formation of novel fusion transcripts and dosage effects from the partial duplication. Subsequent NanoString expression analyses of candidate genes within the CMTX3 locus, across different stages of neuronal differentiation, identified spatiotemporal dysregulation of SOX3. NanoString showed reduced SOX3 expression in patient iPSCs. RNA sequencing detected SOX3 downregulation in CMTX3 neuroepithelial progenitor cells, which was further confirmed by quantitative proteomics. Given the early onset and relatively rapid progression of CMTX3, these data prioritise SOX3 as a leading candidate gene, consistent with its role as one of the earliest transcription factors expressed in the developing nervous system and a key regulator of neuronal fate.

Humans↗

PubMedDate not supplied

The selective impairment of the perception of first-order motion by unilateral cortical brain damage.

First-order (Fourier) motion consists of stable spatiotemporal luminance variations. Second-order (non-Fourier) motion consists instead of spatiotemporal modulation of contrast, flicker, or spatial frequency. In spite of extensive psychophysical and computational analysis of the nature and relationship of these two types of motion, it remains unclear whether they are detected by the same mechanism or whether separate mechanisms are involved. Here we report the selective impairment of first-order motion, on a range of local and global motion tasks, in the contralateral visual hemifield of a patient with unilateral brain damage centered on putative visual areas V2 and V3 in the medial part of the occipital lobe. His perception of second-order motion was unimpaired. As his disorder is the obverse of that reported after damage in the vicinity of human visual area MT (V5), the results support models of motion processing in which first- and second-order motion are, at least in part, computed separately at the extrastriate cortical level.

Aged↗

PubMedDate not supplied

[The variation of two types of spatiotemporal organization of brain potentials at different stages of a cognitive set based on illusory perception of length (Muller-Layer illusion)].

The spatiotemporal organization of brain potentials (STOP) under conditions of their multichannel recording was studied was studied in 35 young healthy subjects during formation, actualization, and extinction of the cognitive set on the basis of illusory perception of length (Müller-Layer illusion) by means of quantitative comparison of successive electroencephalotopograms (ET). The ET is an array of momentary values of potentials simultaneously recorded in all the derivations. An ET is characterized by a relief and mean level. Time changes in these characteristics determine a certain type of cortical STOP. Two main types of STOP were revealed. The interaction between these two types of STOP depended on the kind of performance of a subject and was ferlected in the coefficient of dynamic variation (CDV) of ETs. The CDVs were significantly different in subjects with stable and unstable forms of the cognitive set; in the latter this value was higher. The spectral characteristics of the EEG and STOP dynamics were compared. Analysis of power stectra revealed the significant intergroup differences in the alpha 1 frequency range both in the EEG and STOP; the power of this frequency range was higher in subjects with the stable set.

Adolescent↗

PubMed2025

Tracking microplastic contamination across seasons in a freshwater reservoir: Evidence from surface water, sediments, and fishes.

Microplastics (MPs) are prevalent contaminants in aquatic environments, posing substantial ecological and health risks. These particles migrate within the different layers of aquatic bodies with time and affect the respective biota. Thus, to get an in-depth understanding of the particles, this current study investigated the seasonal distribution, morphological and chemical characteristics, along with potential ecological and human health impacts in the samples including surface water, sediment, and fish from a drinking water supplying reservoir in eastern India. Across three different seasons, pre-monsoon, monsoon, and post-monsoon samples were collected using optimized methods. Results revealed distinct seasonal trends: MP abundance in surface water peaked during the monsoon (mean: 1.15 MPs/L), while sediment showed the highest concentrations in the pre-monsoon (mean: 596 MPs/kg), indicating temporal accumulation dynamics influenced by runoff, hydrodynamics, and sedimentation. Fish gut analysis confirmed ingestion of MPs across five species, with concentrations ranging from 26 to 100 MPs/kg, depending on feeding habits. The most dominant MP type were fragments, followed by fibers, films, and beads. Polymer analysis via µFTIR identified polyethylene, polypropylene, and polyvinyl chloride as prevalent, with hazard assessments (i.e., Polymer Hazard Index (PHI)) indicating medium to very high ecological risks. Heavy metal association was more dominant in the MPs isolated from sediments than the waterborne MPs. Pollution Load Index (PLI) values were > 1 in most seasons, confirming contamination. Health risk analysis suggested potential exposure through both drinking water and fish consumption. This study emphasizes the need for seasonal monitoring, improved waste management, and mitigation strategies to address MP pollution in freshwater ecosystems.

Microplastics↗