Rhizophora mucronata across a > 3,000 km coastal stretch in the Western Indian Ocean (WIO) including WIO islands. Based on 359 trees from 13 populations and using 17 polymorphic microsatellite loci we detected genetic breaks between populations of the (1) East African coastline, (2) Mozambique Channel Area (3) granitic Seychelles, and (4) Aldabra and northern Madagascar. Genetic structure, diversity levels, and patterns of inferred connectivity, aligned with the directionality of major ocean currents, driven by bifurcation of the South Equatorial Current, northward into the East African Coastal Current and southward into the Mozambique Channel Area. A secondary genetic break between nearby populations in the Delagoa Bight coincided with high inbreeding levels and fixed loci. Results illustrate how oceanographic processes can connect and separate mangrove populations regardless of geographic distance.Estimates of population structure and gene flow allow exploring the historical and contemporary processes that determine a species’ biogeographic pattern. In mangroves, large-scale genetic studies to estimate gene flow have been conducted predominantly in the Indo-Pacific and Atlantic region. Here we examine the genetic diversity and connectivity of  Efforts to fill this gap are valuable, as connectivity determines the genetic diversity and structure of populations, increases the effective population size, while high connectivity can replenish degraded sites. Insights in connectivity are therefore essential for effective conservation management. In a broader perspective, a better qualitative and quantitative understanding of mangrove connectivity would provide an interesting biogeographic comparison with systems that have a circumtropical overlap in their range but show distinct differences in their dispersal traits .In coastal and marine systems, where ocean currents may transport individuals over 100–1000 s of kilometres, population genetic approaches strongly promoted connectivity research during the last three decades. Interestingly, a recent quantitative assessment of this research revealed important taxonomic and geographical biases, with mangrove population connectivity having received minimal attention compared to for example fish, seagrasses and corals2. The global spatial coverage of mangroves is estimated at ~ 137,000 km2, spanning the territories of more than 100 countries3. Nevertheless, the consequences of climate change such as accelerated sea-level rise, storm intensification, and changes in temperature and precipitation regimes4, as well as human activities, such as urbanization, aquaculture and agriculture5, alter the distributional range of mangrove forests.Mangroves consist of woody salt-tolerant plants that are morphologically and eco-physiologically adapted to the dynamic conditions of the intertidal zone. They are found on coastal, estuarine and deltaic tidal flats, predominantly at tropical and subtropical latitudes7 and the dispersal of water-buoyant propagules  via near-shore, coastal, and open-ocean surface currents8. While pollination operates at local scales, propagule floating and viability periods of several months9 allow for local-to-global scale dispersal and connectivity12. The spatial scale of connectivity ultimately depends on the additive effect of different factors, such as propagule traits, the timing of propagule release, physical barriers, the availability of suitable habitats, and the spatiotemporal characteristics of the dispersal vectors13. Oceanographic features such as eddies and regions of convergence may constrain, delay or prevent gene flow between nearby populations, rendering the isolation-by-distance (IBD) model too simplistic to explain observed genetic differentiation14. Using nuclear microsatellite markers and a Lagrangian particle-tracking model, a strong genetic discontinuity was found between Rhizophora racemosa G. Mey populations at both sides of an oceanic convergence zone in the Gulf of Guinea15. Similarly, genetic structure of Rhizophora mucronata Lam. populations along the Malay Peninsula was explained by prevailing ocean currents and the species’ dispersal potential, and not by geographical distance17. Indeed, as more species are being studied, biogeographical “barriers” seem more permeable than previously thought and act as filters rather than impenetrable barriers18.Gene flow in mangroves is determined by insect, wind, and bird pollinationAvicennia and Rhizophora species in Southeast Asia24, Central and South America29, and East Atlantic31, with only limited attention for mangrove populations in the Western Indian Ocean (WIO) in general (but see32). Several large-scale mangrove genetic studies have considered samples from the WIO region21, but the majority of locations and the focus in these studies were centered on the Eastern Indian Ocean (EIO) region.Although the amount of mangrove genetic and phylogeographic data is increasing, most studies have focused on populations of Rhizophora mucronata has a distributional range stretching across mangroves of the Indo-West Pacific (IWP) region, from the East African shorelines to the Western Pacific33, with its southern limit in Southeast Africa and its northern limit in the Persian Gulf34  in the Western Pacific. It is the only Rhizophora species in the WIO33 and has one of the widest ranges of all mangrove species. Even-though its global conservation status currently is of ‘least concern’, its global population is decreasing due to residential and commercial development, logging and wood harvesting, agriculture and aquaculture, and potentially climate-induced habitat alteration36.f34 Fig. a. The noR. mucronata in the WIO region. This region is characterised by the bifurcation of the South Equatorial Current (SEC) and the complex circulation system of the Mozambique Channel that is dominated by energetic southward moving eddies38. As a null-hypothesis, we considered that over a broad geographical scale, R. mucronata populations in the WIO would comprise a single evolutionarily significant unit and hypothesise that (1) highest genetic diversity levels will be found for populations located in the core region of the species’ distribution, whereas lower levels of genetic diversity will be found for populations on remote small islands; (2) spatial patterns of genetic differentiation will align with patterns of dominant contemporary ocean currents. For this purpose, we sampled 13 R. mucronata populations distributed across the western extent of its range  to 0.416 (KEN) , the effective number of alleles was 1.5 (1.3–2), whereas the allelic richness ranged from 1.7 to 2.8 (at k = 34 gene copies) for comparison of allele diversity between populations . Within population FIS ranged from 0.381 (MOZ2) up to 0.690 (MOZ5) with all populations significantly inbred (Table R. mucronata were significantly high in most populations (S = 0.45–0.89), except for MOZ1 and ALD2 (Table FIJ of 0.271.The within population inbreeding coefficient 0.381 MOZ up to 0.0.381 MOZ up to 0.FIT of 0.609 (p < 0.001) and a population differentiation AMOVA-FST of 0.281 (p < 0.001)  for the grouping of the Aldabra-Madagascar populations  versus all other populations. When considering a hierarchy of three regions, highest values  were obtained when grouping East Africa , versus Aldabra and Madagascar, versus all other populations . A hierarchical AMOVA considering four regions (Table FRT = 0.185 (p < 0.001). Overall connectivity between populations is very low with an estimated Nm less than 1. Pairwise FST values between populations varied between 0.002 and 0.529 . A Mantel test for all 13 populations suggested isolation by distance , but with a low predictability for Euclidean distances (r2 = 0.24). A more precise test of IBD was performed at the level of individual pairwise kinship coefficients using four classes of increasing geographic distances. Significantly higher than average kinship values were found for the first distance class up to 260 km—average 136 km—, and the second distance class up to 500 km—average 385 km—. The ln-transformed b-slope was − 0.078 (p < 0.001) over a full range of 3008 km.Global inbreeding reached an AMOVA-1) Table . Global ns Table , namely Rhizophora mucronata trees from the Seychelles showed intermediate allele diversity, only few fixed loci, several nearly private alleles at high frequencies, and hence, did not separate as a group, unless along the third axis (11%). A population assignment test gave an average of 71% of the individuals assigned to their own population. However, MOZ1 and MOZ2 individuals could be assigned largely to other populations, whereas individuals from SEY were assigned solely to their own population.A PCoA of individual genotypic distances had both axes explaining a nearly similar amount of variance Fig. . A firsttructure analysis according to the Delta K estimation supported K = 3 clusters (Mean LnP(K) = − 7390, Delta K = 54) or nearly as likely also four clusters (Mean LnP(K) = − 6990, Delta K = 42), the latter with more admixed individuals  appeared less differentiated from those of the African coastline. K = 11 subdivided up to population level, except for East Africa , an admixture in Mozambique (MOZ1 to MOZ4) and on Aldabra . When testing for diversity differences between the K3 clusters, a higher allele diversity (p = 0.011) and gene diversity (p = 0.002) was found in the two East African sites (Ar = 2.8 and He = 0.410) than in the sites of the Mozambique Channel and SEY (Ar = 2.3 and He = 0.280) and Aldabra/Madagascar (Ar = 2.1 and He = 0.200). When considering K4, there were only few individuals (N = 29 out of 359) containing but a limited number of private alleles (PA = 24), all at lowest frequencies such that these private alleles do not explain much of the obtained genetic structure.A Sigrate-n was used to estimate the migration pattern along the Mozambique Channel which was best supported by a unidirectional stepping-stone model (Table Nem = 10.89) and MOZ2 to MOZ1 (Nem = 11.51). All other Nem estimates of more distant populations were below 1. Further specific testing on directionality according to the SEC and on a most likely historical source of the Aldabra population and mainland African coast for migration between the Seychelles (SEY); northern Madagascar (MAD2), Aldabra (ALD1) and the African coast (MOZ2) gave the best support for a stepping-stone model (Table Nem = 0.81) and from Madagascar towards Aldabra (Nem = 0.78). Historical connectivity between Aldabra and the African coastline reached Nem = 0.65.Mel Table . The direl Table , with hiFST matrices), and to a lesser extent (ii) the Seychelles from Aldabra with seven counts, the Seychelles from East Africa (KEN) with six barrier counts, Aldabra from northern Mozambique (MOZ1) with six barrier counts, and the Southern Mozambican population MOZ4 from MOZ5 with 4 barrier counts. Contemporary kinship values of individual R. mucronata trees among populations reached an overall FIJ = 0.102, though with large variation between pairs, namely with high values for most pairs of neighbouring populations (FIJ ranging from 0.111 to 0.289) except for those pairs where a genetic break was observed (FIJ ranging from zero to 0.051). The latter breaks along the East African coastline were between TAN and MOZ1, MOZ4 and MOZ5, MOZ5 and MOZ6. The Seychelles population had zero kinship with Aldabra and Northern Madagascar.The most relevant genetic barriers Fig. , betweenR. mucronata populations of East Africa as more recent than those of Madagascar and the Seychelles. The estimated divergence time of R. mucronata populations of the eastern WIO island populations (SEY and MAD2) appears approximately twice as old. Considering a generation time of about 20 years for R. mucronata, albeit with much potential overlap between generations, the divergence times along the East African coastline could be rather recent and roughly within the Holocene.Comparing the five scenarios of the ABC approach, the highest value of posterior probability (0.338) and 95% confidence interval (CI 0.329–0.346) was obtained for scenario 3 Fig. . This inRhizophora mucronata from the Western Indian Ocean (WIO) showed a clear genetic structure, largely corresponding to the dominant ocean currents in the region. A major genetic break was apparent between populations on the islands of Aldabra and northern Madagascar, and those on the mainland African coast, whereas the granitic Seychelles (located > 1100 km northeast of Aldabra) showed a slightly separate position. Genetic connectivity usually can be expected up to a few 100 s of km. However, genetic breaks were also found on a smaller spatial scale near the bifurcation of the South Equatorial Current (SEC) and between southernmost populations of the Mozambique Channel. The highest levels of genetic diversity are found along the East African coastline where a bifurcated SEC reaches the continent, whereas the lowest allelic richness was found for populations on remote small islands and in peripheral populations in the southernmost region of the Mozambique Channel. High levels of inbreeding were noticed within most sites, as a result of a mixed mating system of the species.Information retrieved from nuclear microsatellites in R. mucronata populations in the WIO would comprise a single evolutionarily significant unit, brought along with the SEC, and originating in a transoceanic manner from either nowadays well-differentiated Southeast Asian21 or Australian sources12. Combined conservative chloroplast DNA and nuclear ITS data indicated a deeper Australian origin12, whereas microsatellite markers reflected contemporary genetic structures21. Within the WIO we found no evolutionary signals over a 3000-km distance, neither in the microsatellite allele sizes (RST = zero) nor in private allele frequencies, which indicates more recent colonization compared to the Eastern Indian Ocean (EIO) and expansion of R. mucronata in the region. The share of a large number of common alleles could eventually suggest a stronger influence of environmental conditions during the Last Glacial Maximum  on the genetic structure within the WIO. The demographic evolution scenarios that we tested were from diverse locations featured by separate gene pools as shown in our Structure and Barrier analysis. ABC tests indicate that the Seychelles and Madagascar (including Aldabra) gene pool, within the context of the currently studied populations, most likely resulted from ancestral migration events, relatively, about twice as old when compared to the gene pool of more westerly located populations on the East African coastline. All events were estimated at only a few thousand generations ago, hypothesised approximately a timeframe within the Holocene, though the latter needs to be thoroughly tested using large-scale phylogeographic studies and preferably based on maternally inherited chloroplast genome sequences information. We assume that population expansion history of R. mucronata in the WIO is characterised by at least two separate ancestral gene pools, namely on the granitic Seychelles and on Madagascar. More recent gene pools may account for the detected patterns along the East African coastline.Prior to our study we considered the null-hypothesis that over a broad geographical scale, AR, HS, FST, Dest) and structure variables  consistently evidenced a contemporary genetic break between mangrove populations of northern Madagascar and Aldabra versus all other populations, as well as the Seychelles granitic islands, reflecting a complex colonization history of the islands. Coastal areas in northern Madagascar may have been populated by sea-faring propagules transported from the east, via the SEC. Despite the westward directionality of the SEC, broadly along these Madagascan populations, this would require dispersal over 6000 + kilometres, as the most proximate large mangrove populations are situated in Southeast Asia or northern Australia. However, direct and reciprocal dispersal across the Indian Ocean may occur via the SEC and seasonally reversing monsoon currents, particularly for propagules with longer floating and viability periods40, such as found in R. mucronata9. The latter hypothesis of reciprocal dispersal should be tested with materials from the northern part of the WIO. When approaching the central eastern coast of Madagascar, the SEC branches into the North-East Madagascar Current (NEMC) and the South-East Madagascar Current (SEMC)  4; Fig. 1.R. mucronata populations in Aldabra and northern Madagascar strongly suggest that the Aldabra Atoll was populated from nearby sources on northern Madagascar. Aldabra populations are extremely isolated by their position on a small and remote island, far away from more extensive and continuous mangrove stands. Moreover, mangroves occur within the lagoon where conditions are more favourable for establishment34. The unfavourable conditions of the atoll’s outer rim could drastically reduce the establishment of propagules from source locations such as northern Madagascar, located about 420 km southeast of the Aldabra Atoll. Hence, any input of genetic material from other populations via long-distance dispersal is assumed to be seldom throughout its recent history. Allelic data shows that colonisation occurred on more than one occasion, as suggested also for terrestrial vertebrates such as giant tortoises42. These cycles of recolonization were interrupted by variations in sea level, which have strongly affected the atoll’s land area and environment, with a complete submergence during the last interglacial period (ca. 125 ka BP)43.The characteristics of these currents, the genetic similarities and migration scenario’s between R. mucronata populations contain more than two alleles for most polymorphic loci, thus beyond the maximum allele diversity that a single diploid founder may bring along. Allele size differences within the Seychelles were not larger than for other WIO populations, indicating either an admixture of populations or in-situ mutations to explain their multiple allele status. While the SEC provides an important vector for the transoceanic transport of propagules, previous studies reported that the zonal flow of the SEC creates a barrier for connectivity between the granitic Seychelles and more southerly positioned populations44. This is consistent with a genetic “isolation” of the granitic Seychelles from Aldabra and Northern Madagascar, although various migration models indicated a historical role of the Seychelles in the connectivity between islands. Moreover, the ABC analysis supported both the Seychelles and Madagascar as an ancestral divergence, which might explain the support of a unidirectional model in Migrate-n albeit with very low gene flow values. Mangrove populations on the Seychelles are likely maintained by propagules from sources of the northern part of the WIO, via the SECC. During the winter monsoon, the Somali Current flows southward, meets the northward flowing EACC, supplying water for the eastward flowing SECC41. This confluence and eastward flow occur at latitudes of the granitic Seychelles and enables propagule transport from mainland mangrove populations to these islands. This could not be detected from nuclear microsatellite markers and additional chloroplast sequence information could provide valuable information for unravelling patterns of connectivity between the Seychelles, Madagascar and other African populations. Nuclear genes and chloroplast sequences of Bruguiera gymnorrhiza (L.) Lamk. indicated a relatedness of Madagascar populations to those of the EIO45 and cpDNA of the widespread Xylocarpus granatum J. Koenig showed a most common South China Sea haplotype in several WIO populations46.At least more than a single propagule reached the granitic Seychelles or, alternatively, different cycles of colonisation may have occurred, because there, 40. However, the spatial density and spread of our sample sites did not allow us to test the latter scenario.A north-to-south gradient of allelic richness characterised the African mainland sites with highest diversity values in Kenya and Tanzania, north of the SEC bifurcation. The mangrove sites influenced by the EACC appear to have received and sustained more migrants than other areas although, based on our ABC analysis, this appeared to have occurred during more recent rather than ancestral times. The SEC very likely sustained these populations with a historically accumulated input of migrants from remote easterly mangrove populations, located within or beyond the WIO. While this scenario could suggest the expectation to observe the highest genetic diversity in (northern) East Madagascar, spatial differences in the availability of suitable geomorphic and sedimentary settings for mangrove establishment may present higher chances of opportunistic colonization on the East African coast compared to the higher-energy coast of East Madagascar. Importantly, migrants from eastern populations may have also arrived via populations in the Arabian Sea and Gulf of Bengal, as suggested in previous studiesR. mucronata populations with the highest kinship values, and even appeared as a single gene pool from the Structure outcome at K11. Similar evidence of high connectivity alongside this part of the East African coast was also observed in other taxa, such as the stony coral Acropora tenuis47 and the seagrass Thalassia hemprichii48. Likewise, a higher genetic diversity and stronger connectivity was observed for the populations of northern Mozambique (MOZ1 and MOZ2) as compared to the more distant southernmost populations in the Mozambique Channel. Overall, the core region of mangrove populations, situated at latitudes of the SEC , seems to harbour the most diverse R. mucronata populations. Such enhanced diversity levels in a zone of largest and most direct—perpendicular—SEC influence could become a more general hypothesis because Avicennia marina mangroves also showed highest allele diversity in Kenya and Tanzania in comparison to South Africa32. Strong genetic differentiation between populations along the northern East African coast (TAN and KEN) and populations located in the Mozambique Channel  corresponds with the SEC bifurcation. These distinct gene pools most evidently originate from a historically different accumulation of migrants and the opposite directionality of ocean currents hampering mutual propagule exchange50. One may assume that besides the SEC sorting migrants at bifurcation, subsequent differentiation and sorting in a stepping-stone manner may have occurred northwards and southwards along the East African coastline.Over a 225 km distance, KEN and TAN were the most connected igrate-n analysis indicated MOZ2 as a population with detectable Nem input. Experimental and modelling studies in the Mozambique Channel have demonstrated the capability of cross-channel transport between Mozambique and Madagascar within 19–30 days, likely facilitated by the frontal zones between eddies and the associated interstitial waters of the turbulence field50. This potential for cross-channel transport was also demonstrated in a large-scale WIO population genetic study of the seagrass T. hemprichii, suggesting Madagascar as a potential source for main African populations48. The remote Seychelles population could be occasionally connected to northern Madagascar and to the coast of the African mainland, though the input source of migrants will be far too limited to leave a detectable trace in a vast area of existing mangrove forests. Whereas it appears that the Seychelles would share a common gene pool with MOZ1 and MOZ2 for K3, all SEY individuals were 100% assigned to their own population.The geographical position of MOZ2 at the southern bifurcation of the SEC and starting point of eddies in the Mozambique Channel could be hypothesised as a crossroad. A genetic connectivity from the eastern part of the Mozambique Channel (northern Madagascar or Aldabra) towards MOZ1 and MOZ2 could not be detected with certainty, but only indirectly inferred; the MR. mucronata populations are poorly differentiated and all share a common genetic cluster at K3. This gradient and connectivity is likely to be maintained by the generally southward flowing current along the Mozambique coast51 and the anti-cyclonic circulation pattern in the region, which is believed to facilitate an almost random dispersal and homogenise populations along the East African coast54. Despite the dominance of southward flow in the Mozambique Channel, propagules might be transported both southward and northward through the Channel within periods of 51–207 days, via the frontal flow field between eddies51. These time spans are within the range of buoyancy and viability periods observed in R. mucronata propagules9. Along the southward component of the SEC, and further south along the Mozambique Channel, a gradient was apparent in R. mucronata populations for their lowered allelic richness and gene diversities, increased inbreeding levels, number of fixed loci and an admixed assignment of individuals for genetic clustering (cf. K4 and K11). The connectivity between neighbouring populations decreased  and kinship values dropped to zero between MOZ4 and MOZ5, also indicated by low gene flow estimates and a genetic break situated on the Delagoa Bight. An extensive chain of mangrove forest can be found from approximately the northern Kenyan border further southwards up to about 50 km south from the mouth of River Save on the Sofala bank in Mozambique34. However, beyond this point, mangrove forests line the coasts in a less continuous manner and are mostly found in more sheltered inlets34. The populations MOZ3 to MOZ6 are situated in this area of non-contiguous mangrove forests. MOZ3 lies only 100 km south of a 1900 km2 mangrove stand fringing the Sofala Bank, which is considered the largest mangrove area in the region55 and hence might provide a higher number of propagules for dispersal. MOZ4, MOZ5 and MOZ6 are located ca. 300–800 km from the extensive Sofala Bank mangrove stand. Therefore, we hypothesise that migrants from the Sofala Bank favour higher diversity in MOZ3 and MOZ4 when compared to the Delagoa Bight populations, MOZ5 and MOZ6.Within the Mozambique Channel, 51, flowing southward without entering the Delagoa Bight. Additionally, the Delagoa Bight is characterised by mesoscale features such as countercurrents and eddies56 and consists of a large extended shelf area where lies a quasi-permanent lee eddy57. These features may retain propagules from populations in this area (MOZ5 and MOZ6) and prevent dispersal offshore58. A sharp gradient in genetic diversity was also observed in the spiny lobster Panulirus homarus and separated even evolutionary units of subspecies at the Delagoa Bight59. It is most probable that both the lee eddy of the Delagoa Bight and the jet current prevent propagules from northward populations to strand in the Delagoa Bight. Subsequently, the mixed mating system of R. mucronata may promote high inbreeding values and many fixed loci as were noticed in the well-connected populations MOZ5 and MOZ6.The genetic break between MOZ4 and MOZ5, despite their geographic proximity, can be explained by the dynamic hydrography near the Delagoa Bight area. MOZ3 and MOZ4 are located on a protruding land area, where the continental shelf is practically inexistent. A jet current  passes just along MOZ4R. mucronata site is most likely the result of geitonogamy as in R. racemosa60. This can blur the determination of a genetic structure at the population level because occasional fixation of private alleles might lead to enforced clusters of gene pools. However, this situation was not observed in the WIO because R. mucronata populations shared common alleles throughout the region, such that allelic richness (AR) and gene diversities (HE and Dest) determined the detectable patterns of connectivity at population level. High within-site kinship values and estimated selfing rates can be explained from their high frequencies of most common alleles. Rhizophora mucronata is a self-compatible species61. Similar inbreeding levels for R. mucronata have been reported in Southeast Asia and were attributed to the reproductive biology and dispersal strategies of the species16. Interestingly, lower inbreeding values were found in populations of R. racemosa in West Africa15 than in R. mucronata. Rhizophora racemosa’s fruits resemble those of R. mucronata, which suggests that besides reproductive strategy, propagule morphological traits, and dispersal strategies, other factors such as local topography and species zonation (landward/seaward) may influence the local inbreeding level of these coastal populations13.Inbreeding within nearly each R. mucronata of the WIO should be considered as a recent colonization (in comparison to the EIO) with an expansion zone that has particularly led to areas of unicity, of higher diversity, of inbreeding, and of contrasting connectivity even over short distances, which all are relevant in a transboundary context. Anticipating the ever-increasing need for international cooperation regarding the conservation and management of dispersive coastal and marine species, we encourage the integration of available genetic data and models to further increase our understanding of the interplay between the ecology and evolution of mangroves, large-scale  connectivity, and aspects such as species distributions and long-term persistence.In conclusion, our study highlighted that Rhizophora mucronata samples were collected in 13 locations  were performed with the QIAGEN Multiplex PCR kit and consisted of 12.5 μL reactions with 2.5 μL H2O, 6.25 μL of Qiagen Multiplex PCR Master Mix, 1.25 μL primer mix and 2.5 μL DNA. The primer mix consisted of 2 μM of each fluorescence-labelled  microsatellite primer . PCRs were carried out in a BIO-RAD T100 thermal cycler , starting with an initial activation step of 15 min at 95 °C, followed by 35 cycles of 30 s at 94 °C, 90 s at 57 °C and 90 s at 72 °C, and ended with a final extension of 10 min at 68 °C. Fragment analysis was done by Macrogen Inc., after which allele sizes were assessed with the software Genemarker 2.4.0 .Total genomic DNA extraction was performed on 30 mg of dried leaf material using the E.Z.N.A. SP Plant DNA kit  for subsequent microsatellite analysis. A total of 50 previously published microsatellite primer pairs of 68 and no significant genetic linkage (p < 0.05) was found. No scoring errors or large allele size dropouts were indicated using Micro-Checker69, whereas a general excess of homozygotes for many loci suggests the presence of null alleles. This test, however, does not consider the effect of inbreeding situations and therefore INEST 2.270 was applied as a Bayesian approach for estimating both null alleles and inbreeding simultaneously71. The model was run with 50,000 burn-ins and 500,000 cycles and supported for each population a model including inbreeding rather than a null allele model. Three parameters were used for the model comparison: n, null alleles; f, inbreeding; b, genotyping failure. With these three parameters, six models are composed: n, b, nf, nb, bf, nfb . The six models were run with 50,000 burn-ins and 500,000 cycles for each population. A comparison of these models with the lowest Deviance Information Criterion (DIC) outperforming the other models, selected nf (in 8 populations), nbf (in 4 populations) and bf (in 1 population) as best fit, hence putting inbreeding instead of null alleles as a most likely explanation for the lack of heterozygotes. The probability of identity, using Genalex 6.572, was checked for a combination of all loci and ranged from 5 × 10–3 to 9 × 10–8. Multilocus repeats were seldom, namely 16 repeats for 9 MLG’s out of 359 samples. All repeated MLG’s were kept for further analysis, considering the INEST indications of inbred situations.Prior to full data analysis, all pairs of microsatellite loci were tested for linkage disequilibrium with FSTAT 2.9.3 softwareAM), effective number of alleles (AE), observed heterozygosity (HO) and unbiased expected heterozygosity (HE) were calculated using Genalex. Total number of alleles (A), allelic richness (AR), deviation from the Hardy–Weinberg Equilibrium and the within population inbreeding coefficient (FIS) per population were obtained with FSTAT. Deficiency of heterozygotes was assessed after Bonferroni correction using FIS values with 221,000 randomisations. The selfing rate was estimated and based on a standardised identity disequilibrium, assuming a mixed mating model using spagedi 1.573. A population assignment (with leave-one-out option) was done for their proportion of 'self' or 'other' populations with Genalex. The overall pairwise kinship coefficient (FIJ)74 was estimated for all comparisons at the ‘within population level’ using spagedi. To strengthen the evidence at both large and small geographical scales, we intentionally conducted most approaches at the individual level, because population level analysis might become skewed in case of strong inbreeding.The percentage of polymorphic loci per population, mean number of alleles (FST) was performed with Genalex. Additionally, all combinations within a hierarchy of 2, 3 and 4 groups were tested for highest % variance among regions (FRT). To estimate the effects of microsatellite allele sizes, an AMOVA-RST was compared to AMOVA-FST. Pairwise genetic differentiation (FST) and allelic differentiation (Dest) between all populations were estimated and tested for significant differences (999 permutations) using Genalex. A principal coordinate analysis (PCoA) at individual level based on genotypic distances was performed in Genalex. The underlying pattern of genetic structure was determined with Structure 2.3.275, using the admixture model with correlated allele frequencies without prior population information. We carried out 10 replications for 1 ≤ K ≤ 15 with 1 × 105 Markov Chain Monte Carlo (MCMC) iterations and 1 × 104 burn-in. The optimal K was inferred with the ΔK statistic76 and LnPK using Structure Harvester77 calculated with Structureselector78. Two-sided tests for comparisons among three groups  were performed (1000 permutations in FSTAT) to test for differences in their allelic richness, heterozygosity, inbreeding and differentiation. Private alleles were checked for the K = 3 and K = 4 clusters in Genalex.An analysis of Molecular Variance  was used for the genetic distance matrix. To test for genetic IBD at the individual level, an analysis of the pairwise kinship coefficients (FIJ)74 was done using spagedi, namely a spatial autocorrelation for different classes of geographic distances  with estimation of an ln-transformed b-slope over the full range of 3008 km. The overall pairwise kinship coefficient was estimated for all comparisons at the ‘among population level’. The software Barrier 2.279 was used to detect the location of sharp genetic changes between neighbouring populations on basis of one overall pairwise FST matrix and 17 pairwise FST matrices of every microsatellite locus allowing a maximum of two barriers per matrix. To test for these potential genetic breaks specifically between neighbouring populations, an analysis of the pairwise kinship coefficients (FIJ)74, was done for each case of only among population’ pairwise estimation  using spagedi.To detect whether there is a decrease in connectivity among populations with increasing geographic distance, a Mantel test was performed  in Gigrate-n81 was used to estimate the mutation-scaled population sizes (Theta) and immigration rates (M). The Brownian model was tested locus by locus along with the product of distributions of all loci for all individuals in a population. Uniform prior distribution settings  were Theta = 0.0, 10.0, 0.1 and for M = 0.0, 100, 10.0. The number of recorded steps was 106 at a sampling frequency of 103 after an initial burn-in, computing two replicate chains, and using the Bezier thermodynamic integration81 for calculation of the Bayes factors from marginal likelihoods giving model probabilities. The effective number of immigrants per generation (Nem) was calculated as [Theta × M]/428. Panmixia, bidirectional and unidirectional stepping-stone historical migration/expansion models were used for testing the hypothesis of a North to South migration in the Mozambique Channel (MOZ1 to MOZ6). Panmixia, source-sink or stepping-stone models were considered to test a specific hypothesis on directionality for migration among the island populations Seychelles (SEY), northern Madagascar (MAD2) and Aldabra (ALD1), and towards the African mainland (MOZ2).MR. mucronata populations of the WIO was carried out on seventeen microsatellites considered as a single group with dinucleotide repeats, using the Approximate Bayesian Computation (ABC) approach implemented in DIYABC ver. 2.082. The aim of this analysis was to answer a main phylogeographic question that was raised from the genetic Structure and the Migrate-n outcome, namely about the ancestral origin of eastern WIO island populations  and of coastal African populations (East to Southern Africa). Therefore, we considered representative allelic rich R. mucronata populations within each of the of five regions, namely KEN, MOZ2, ALD2, MAD2 and SEY to conduct a model where we specifically conceptualised five scenarios of demographic history 2 distance) were considered for each population or pairwise comparison of samples. Five million simulation data sets were run for the prior distribution and the most-likely scenario was obtained from a comparative assessment of their posterior probabilities. One million simulated data sets were used to compute posterior, of which 10,000 were used in the local regression. From the posterior 1,000 data sets were simulated. The goodness-of-fit was checked through principal component analysis (PCA) using the ‘model checking’ option. The posterior distribution of parameters (N# and t#) was estimated.In all scenarios, t# represents the time scale measured in number of generations (largest numbers refer to oldest events) and N# represents the effective size of the corresponding populations during the indicated time period. We used default prior values for all parameters, except for the maximum population size and maximum values of time scale  based on the outcome of the preliminary test runs of prior distributions. Summary statistics of 65 variables (mean number of alleles, mean gene diversity, mean allele size variance, Supplementary information.


N-(phosphonomethyl)-glycine] is a herbicide with several commercial formulations that are used generally in agriculture for the control of various weeds. It is the most used pesticide in the world and comprises multiple constituents  that help to effectively reach the action’s mechanism in plants. Due to its extensive and inadequate use, this herbicide has been frequently detected in water, principally in surface and groundwater nearest to agricultural areas. Its presence in the aquatic environment poses chronic and remote hazards to human health and the environment. Therefore, it becomes necessary to develop treatment processes to remediate aquatic environments polluted with glyphosate, its metabolites, and/or coadjutants. This review is focused on conventional and non-conventional water treatment processes developed for water polluted with glyphosate herbicide; it describes the fundamental mechanism of water treatment processes and their applications are summarized. It addressed biological processes , physicochemical processes , advanced oxidation processes—AOPs  and combined water treatment processes. Finally, the main operating parameters and the effectiveness of treatment processes are analyzed, ending with an analysis of the challenges in this field of research.Glyphosate [ In recent years, the global food demand caused by population growth has motivated an intensive use of agrochemicals in agricultural activities. However, this can cause an environmental impact ,2. One oN-(phosphonomethyl)-glycine] has a highly effective foliar action herbicide because of its characteristics: I) It is a systemic herbicide because inhibits the 5-enolpiruvil-shikimato-3-phosphate-synthetase enzyme (EPSP), which is indispensable in essential amino acids synthesis for plant growth and development. This herbicide causes leaf decomposition and therefore the plant death between 5 to 30 days after application [−1 at 25 °C) this herbicide can be easily detected in surface water and groundwater [1/2 glyphosate from 7 to 315 days, most commonly 45–60 days and t1/2 AMPA from 76 to 240 days), it can persistence in water [Glyphosate or [lication ,7,8; II)lication ,7,8. Thilication ,9. Becauundwater . The surundwater ,10. In tin water ,12. For Regarding ecotoxicology, once the herbicide (dose) enters the organism, it can have a toxic effect, which can be in the short (acute), medium  and long term (chronic). Eco-toxicological studies have determined that glyphosate affects several aquatic trophic levels (freshwater/marine environments), being more toxic than the commercial formulations ,13. In tThis review describes the fundamental mechanism and presents some applications of these treatment processes studied for water polluted with glyphosate herbicide. It includes the basic concepts of each technique, operational conditions, and their effectiveness in water treatment. Conventional and non-conventional treatment processes are described. Biological treatment processes such as bacterial and fungi degradation, physicochemical processes—principally adsorption and membrane filtration—AOPs such as Fenton-based processes, UV-based process, and electrochemical oxidation like anodic oxidation and photoelectrocatalysis, and combined water treatment processes are analyzed. Finally, the challenges in this field of research are analyzed.Achromobacter spp., Agrobacterium radiobacter, Alcaligenes sp. GL, Arthrobacter spp., Bacillus cereus CB4, Ochrobactrum spp., Pseudomonas spp., Aspergillus niger, Aspergillus oryzae A-F02, Penicillium chrysogenum, Trichoderma harzianum, among others.Glyphosate biodegradation by microorganisms has been described as a safe, cost-effective and reliable means to remove this pollutant from soil and water . BiodegrPseudomonas sp., Bacillus cereus, Arthrobacter sp., Ochrobactrum sp., Achromobacter sp., Alcaligensis sp., Flavobacterium sp., Agrobacterium radiobacter sp., and others. Similar to bacteria, fungi species also utilize glyphosate as a source of phosphorus and nitrogen nutrients for their growth, and use analogous enzymes in the degradation pathway [Glyphosate biodegradation in bacterial species has three transformation pathways . The fir pathway .Trichoderma viridae, Aspergillus niger, Aspergillus Oryzae, Fusarium oxysporum, Trichoderma harzianum, Scopulariopsis sp, Penicillium citrinum. Degradation pathways of glyphosate in fungi and bacterial species are summarized in On the contrary, the fungi biodegradation pathway of glyphosate is shorter than the microbial pathway because fewer secondary metabolites are formed . AMPA isFlavobacterium sp. was the first microorganism identified which can metabolize glyphosate, AMPA and sarcosine; it was applied in activated sludge to treat glyphosate-containing wastes at Monsanto Co. wastewater treatment plant [Agrobacterium radiobacter was isolated from a bench-scale sequencing batch reactor degrading a waste stream containing glyphosate, it utilizes glyphosate as a sole source of carbon and energy [Pseudomonas spp. is able to remove higher than 98% using a biofilm colonized with bacteria in immobilizing bacterial technology columns (IBT) [Pseudomonas sp. and Bacillus sp. together are an effective microbial culture for biodegrading glyphosate in contaminated soils and aquifers [Based on the above, several authors have studied biological treatment to remove glyphosate and AMPA from water: nt plant . Agrobacd energy . Pseudomns (IBT) ; a biolons (IBT) ; native ns (IBT) . Pseudomaquifers ; unaccliaquifers .Streptomyces sp., Bacillus subtilis, Rhizobium leguminosarum), which were useful in bioremediation of glyphosate polluted environment [Fusarium oxysporum strains were capable of biodegrading glyphosate in pure and consortium cultures in a platform shaker and batch bioreactor, they achieved about 41% degradation efficiency after 5 days of culture [Trichoderma harzianum has been found to have AMPA-degrading activity and achieved 69% of AMPA degradation after 10 days of incubation [Aspergillus oryzae A-F02 isolated from an aeration tank in a pesticide factory, which can transform less than 50% of glyphosate to AMPA after 72 h of incubation [In the most recent study, Singh et al.  evaluateironment . Fungal  culture . Trichodcubation , a recencubation .As shown above, the biologic treatment appears to be a promising process to remove glyphosate from water. However, this process could present some disadvantages. First, to evaluate the potential of glyphosate-degrading microorganism, it is important to enhance some experimental conditions such as initial pH, incubation temperature, glyphosate concentration, inoculation biomass and incubation time, because all of them are important operational parameters to optimize bioremediation of real water polluted with glyphosate. Second, under controlled conditions, some microorganisms use glyphosate as a sole source of nitrogen or phosphorous, however, in natural ecosystems, their efficiency in glyphosate degradation may drop significantly because, in the majority of cases, the expression of some enzymatic complex  is activPhysicochemical processes are efficient and economical methods in pollutant removal from water and wastewater. Various physicochemical processes such as adsorption, membrane filtration, and coagulation have been studied at laboratory and pilot scales with the common target of removing glyphosate from water. However, adsorption and membrane filtration technologies have been widely studied. Some studies about the remotion of glyphosate from water polluted by psychochemical processes are summarized in 2, and -PO(OH)2) and adsorbent surface. Adsorption has been widely studied due to its simplicity, low-cost, easy operation with high processing efficiency and high removal rates of most pollutants . The keyPhysical adsorption is mainly caused by the forces of molecular interactions including permanent dipole/induced dipole, Van der Waals dispersion forces as well as hydrogen-bond with acid groups like -OH and -COOH on the material surface , but als2+ and Fe3+ ions forming stable single-tooth or bidentate complexes, thus facilitating the adsorption significantly [Chemical adsorption occurs due to electrostatic attraction between the glyphosate molecule and adsorbent surface, which is strongly influenced by pH conditions. In acidic conditions, glyphosate shows a negative charge, so it is attracted to the material’s surface with a positive charge ,49. Addificantly .A graphical representation of possible mechanisms for glyphosate adsorption is illustrated in –1 based on the Langmuir model [Many adsorbent materials have been studied for removing glyphosate from water and wastewater . Currentir model .−1 for dewatered alum sludge (DAS) and 113.6 mg·g−1 for liquid alum sludge (LAS), with a removal efficiency of 91.6% and 97.4% respectively [3O4 to obtain magnetic reduced graphene (RGO/Fe3O4); could achieve a satisfactory adsorption performance for low GLY concentrations (1–40 mg·L−1) with removal rates higher than 86% by adding 10 mg of RGO/Fe3O4 [2O3); which after 2 h of equilibrium time the maximum removal was 92% at 15 °C [Alum sludge has exhibited the potential to be an efficient and cost-effective adsorbent for glyphosate removal with excellent immobilization ability, two studies have used it as an adsorbent. The first study reported a maximum glyphosate adsorption capacity calculated from Langmuir’s isotherm of 85.9 mg·gectively , and theectively . AdditioGO/Fe3O4 , and graat 15 °C .−1 showing great potential for high glyphosate concentrations removal in wastewater [Montmorillonite is a 2:1 type aluminosilicate that has been proposed as an adsorbent for glyphosate removal. Glyphosate molecules accommodate between the layers which increases the interlayer space, XRD patterns show a displacement in the peak that corresponds to (001) plane due to the intercalation compound formation. Adsorption of glyphosate in montmorillonite may be enhanced by the presence of Fe(III), the maximum adsorption capacity was greater than 210 mg·gstewater . Kaolinistewater .As can be observed, even though the adsorption process seems to be an effective way to remove glyphosate from water, the majority of reports have been studied at laboratory scales using synthetic water. Additionally, the main disadvantage of water treatment by adsorption is the residue produced and the not-easy reuse of adsorbents. Thus, in order to scale adsorption technology, it requires to promote the efficiency of adsorbents for glyphosate removal in natural waters and the recovery of adsorbents after-treatment process. Modification of the existing low-cost adsorbents is one of the most significant strategies to improve their performance; however, the main challenge with the use of adsorbents is their low selectivity by co-existing compounds in real water samples. Therefore, the design of an adsorbent with enhanced both capacity and selectivity can be considered as one of the most important research objectives for glyphosate remotion from water. Finally, adsorption treatment has some disadvantages the adsorption efficiency of glyphosate has been better at acidic pH levels, this has implications at the treatment plant application because it determines pH adjustment of the influent. Over the last few years, membrane filtration technologies have been used in many areas of water and wastewater treatment. This system works as a barrier for matter transport of an influent stream and separates it into two effluent streams: the permeate and the retentate or concentrate ,53. The Liu et al.  and Sait2 y NaCl). The results demonstrated that with an initial concentration of 50 µg·L−1 and 2.5 MPa of trans-membrane pressure (TMP), the rejection percent is 82.8–91.5% for glyphosate and 73.5–86.7% for AMPA. Intermediate concentrations of NaCl and humic acid showed little influence on the glyphosate-retention; on the contrary, CaCl2 shown a negative effect during the nanofiltration process. However, rejection performance slightly improved when coexisted humic acid and CaCl2 [Therefore, there is a need for evaluating the effect of natural organic matter on glyphosate removal by nanofiltration. Yuan et al.  conductend CaCl2 . Finally2) and mixed it with polysulfone membranes (PSf); GO/TiO2/PSf membranes were used for dead-end flow ultrafiltration system of some commercial herbicides, one of them was glyphosate, from aqueous solutions. The results showed that blended membranes acted based on the size molecule exclusion mechanism and GO/TiO2 nanoparticles in membrane played a key role in the percentage of adsorption of herbicides on GO/TiO2/PSf membrane. Glyphosate rejection was 53% working under the following experimental conditions: dead-end flow ultrafiltration system, glyphosate concentracion (20 ppm), TMP 1 bar and constant temperature (25 °C).The modification of adsorbents structure by means of advanced nanocomposite materials to obtain mixed matrix membranes has been also applied in ultra/nanofiltration systems. Hosseini and Toosi , synthesIn general, filtration by polymeric membranes seems to be an effective method for the removal of pollutants from water, but there is a lack of knowledge about the operation process because neither of the studies has been done in real water. Therefore, there is still room for investigation researching the feasibility of using the nanofiltration process to remove glyphosate from water. Membrane filtration could present some advantages. One of them is that the filtration process does not destroy pollutant molecules so it does not produce harmful intermediates which could be more toxic than original pollutants, another advantage is that the pollutant could be recovered after saturation of membranes. On the other hand, a disadvantage of membrane filtration could be its specificity to reject specific pollutants, but in real conditions, the composition and characteristics of water could suddenly change affecting the efficiency of the filtration process. Therefore, there is a need for evaluating with more detail the effect of natural organic matter on glyphosate removal by nanofiltration and the effectiveness of this treatment for polluted water with commercial formulations because adjuvants (surfactants) could not be rejected if this process were applied in real conditions of polluted water.•OH) plays a central role in AOPs due to its high standard potentials (2.8 V vs. NHE) in acidic media. It is highly reactive and nonselective that can oxidize and decompose organic matter until its total mineralization CO2, H2O, and its corresponding inorganic salt [•OH that lead to cleavage of the C–N and C–P bonds to yield intermediaries such as AMPA and sarcosine or final degradation products such as nitrate, ammonium and phosphate ions, carbon dioxide, and water (Reaction 1). Among AOPs strategies employed to remove glyphosate from water are Fenton and Photo-Fenton process, ozonization (O3), photocatalysis, photolysis with hydrogen peroxide and UV light (H2O2-UV), electrochemical oxidation and photoelectrochemical processes [AOPs have been proposed as alternative methods for water and wastewater treatment, which usually operate at or near ambient temperature and pressure conditions, and they involve the generation of powerful oxidizing agents in sufficient quantity to effective water purification . The AOPnic salt ,55. In trocesses ,55,56. T2+) ion as a catalyst to decompose hydrogen peroxide (H2O2) and convert it to •OH radicals [Fenton and Photo-Fenton processes have the ability to decompose toxic organic molecules in water and wastewaters by means of strong oxidant species produced in aqueous media. The Fenton process utilizes ferrous  and UV-induced reduction of dissolved Fe3+ to Fe2+ (Reaction 4) [Based on the classical Fenton treatment process and in order to enhance the degradation efficiency, some hybrid processes based on Fenton´s reaction (Equation (2)) such as photo-Fenton system and electro-Fenton system have been proposed . In the ction 4) .H2O2 + 2O2 and Fe2+) may be generated through electrochemical reactions, according to Reaction 5 and Reaction 6.In the same context, in electro-Fenton technology, either or both Fenton reagents . After 60 min of photo-Fenton process glyphosate concentration fell down below reaching a remotion of 57% of total organic carbon (TOC) and 0.385 mmol·L−1 phosphate ion as a final degradation product. Additionally, they reported that the toxicity of effluent decreased from 100% to 54% due to less concentration of glyphosate [−1 of glyphosate and AMPA using low Fe(II) or Fe(III) concentrations. Under these conditions, SPF-like and SPF processes led them to reach 70% and 80% mineralization, respectively.There are a few reports on the above-mentioned Fenton’s reaction applied to remove glyphosate from water, some of them are shown in  was 3.5 . Souza e was 3.5  studied yphosate . Recentlyphosate  have exp2+ as a catalyst achieved complete removal of the herbicide (0.1 mM) after 60 min at 200 mA of current applied. Under this process, AMPA was the principal degradation intermediary [2+; pure O2 flow rate = 100 mL·min−1), it achieved a 50.4% of total organic carbon (TOC) remotion and a 72% of chemical organic demand (COD) remotion. The most recent application of Fenton-process using carbon felt cathode showed that the maximal removal percentage of glyphosate was 91.91% with an applied current density of 10 mA·cm−2, pH 3, 0.1 mM Fe2+, 0.05 M Na2SO4, and 0.1 mM as glyphosate concentration under 40 min of treatment. However, only 81.65% of TOC decayed in the same conditions due to the production of some intermediates during the electro-Fenton process that could be more slowly degraded than glyphosate [On the other hand, electro-Fenton-like treatment with Mnrmediary . Anotherrmediary  where acyphosate . As has 2O2; UV/O3) and heterogeneous photocatalysis are two UV-based processes studied to remove glyphosate from water polluted [UV-based processes require yields that leads to enough quantities of powerful oxidizing species to degrade pollutants in water. Photolysis  or catalyst. However, ultraviolet light combined with hydrogen peroxide (UV/H2O2) (Reaction 3) or combined with ozone (UV/O3) increases the quantity of •OH radicals produced [3 is decomposed into O2 and oxygen atom O(1D). O(1D) is very energetic and therefore reacts fast with practically all conceivable substrates, including water to form H2O2 via Reaction 8. To end the reaction process, H2O2 could form oxidant species based on Reaction 3.During vacuum-ultraviolet  the photolysis of pure water is a particularly interesting or powerful source of e et al. , this teproduced . Accordiproduced , upon ph2) [band-gap energy (hν ≥ Eg), being 3.25 eV for TiO2 in anatase phase or 3.05 eV in the rutile phase. The irradiation causes the electrons (e−) of the valence band (VB) to exit and migrate to the conduction band (CB) leaving vacancies or positively charged holes (h+) in the BV. In this way, electron/hole pairs (eCB−/hVB+), where redox reactions are carried out, are generated (Reaction 9). The hVB+ are strong oxidizing agents where water oxidation reaction form •OH radicals or react directly with pollutants on semiconductor surface (Reaction 10); while the eCB− react with electron receptor species such as O2 to form superoxide radicals (O2•−), which also is an oxidant species (Reaction 11) [Another treatment process studied to remove glyphosate from water is heterogeneous photocatalysis. The photocatalytic process has been a successful technology for glyphosate degradation, and in this process, the semiconductor catalyst most widely used is titanium dioxide (TiO2) . Its photion 11) .(9)TiO2+Based on the mechanism described above, some studies about glyphosate removal from water by photolysis and heterogeneous photocatalytic process are analyzed below and summarized in 2O2/UVC process performed with glyphosate solutions in the concentration of 0.30 mM and 0.45 mM or 50–75 mg·L−1, respectively. These glyphosate concentrations were average values of concentration found in wastewaters produced by rinsing herbicide containers [2O2/UVC system for degradation of commercial glyphosate herbicide mixture in water. Both studies compared the results obtained from a mathematical model with the experimental ones. Vidal et al. reported 80% glyphosate remotion and 70% TOC remotion after 12 treatment hours, these results were similar to the percentage remotion reported by López et al. [Manassero et al.  studied ntainers . The effntainers . Other antainers  and Lópentainers  have stuz et al. .2 is effective to remove glyphosate and its degradation intermediaries; after 30 min of photocatalytic treatment of acid glyphosate solution (pH = 10), TOC remotion was 92%. Similarly, Chen and Liu [−1 and of 6.0 g·L−1 of TiO2 as an optimum amount of photocatalyst. Additionally, they analyzed the influence of metallic ions and other species  in photodegradation efficiency, they have reported that 0.0196 mmol·L−1 of Fe3+ and 0.01 mmol·L−1 of Cu2+ were optimal concentrations for the effective remotion of glyphosate from water, whereas optimum values for H2O2, S2O82−, and BrO3 were 0.1, 1.0, and 0.5 mmol·L−1, respectively. Finally, in the study reported by Xue et al. [−1 glyphosate concentration, 1 h of treatment time and synthesized cerium doped TiO2 nanotubes by hydrothermal treatment of rutile TiO2 nanoparticles followed by posterior impregnation.About photocatalysis, the study carried out by Assalin et al.  showed t and Liu  achievede et al. , 76% gly−1; other authors described in this section use a very low concentration of glyphosate. For that reason, it not easy to assume that those processes would be applicable to water treatment on a real scale where glyphosate concentrations could be greater. Furthermore, only one study reports the degradation pathway of glyphosate, showing a lack of knowledge on the degradation route by UV processes. Therefore, more studies are needed with parameters that simulate the real conditions of water in order to study the scaling of UV based treatment processes.Based on UV-based processes analyzed above, only one study reports the formation of degradation intermediates and final products, the rest of them only report the efficiency of glyphosate removal but not the efficiency of mineralization, so in these studies, there could be the formation of intermediate products such as AMPA, sarcosine, glycine, among others. According to Manassero et al, the concentration of wastewater from tank washing is between 50–75 mg·L•OH)) or chemisorbed “active oxygen” ). The action of these oxidizing species leads to complete or partial decontamination, respectively. Comninellis et al. [2 (non-active anodes).Electrochemical Oxidation (EO) is a technology that consists of supplying enough anodic energy to degrade organic matter until its total mineralization or even less complex biodegradable molecules . EO of os et al.  found th2 or IrO2 anodes which interacts strongly with the •OH radicals resulting in the transformation into higher oxide or superoxide chemisorbed at anode surface (MO) (Reaction 13). It allows only partial oxidation of organics (R) forming some organic compounds as short carboxylic acids and others degradation intermediaries, however, it depends on the complexity and stability of pollutants and treatment conditions (RO) (Reaction 14) [Active anodes have low oxygen overpotential, in other words, active anodes are good catalysts for oxygen evolution reaction. It is the case of Pt, RuOtion 14) .M + H2O2, SnO2 or boron-doped diamond (BDD), their surface does not provide any catalytic active site for the adsorption of organics from the aqueous medium, so non-active anodes act only as an electron sink for the removal of electrons. In these anodes, the physio-absorbed hydroxyl radicals (M(•OH)) remain stable, which allows their availability to achieve complete pollutant’s mineralization (Reaction 15) [In contrast, in non-active anodes, such as PbOtion 15) .(M)•OH 2O2) and persulfate (S2O82−), percarbonate (C2O62−), and perphosphate (P2O84−) ions; the last ones could be present in the solution according to the following reactions [The process described above does not need to add oxidation catalysts to the solution and does not produce any byproducts. However, indirect electrolysis of pollutants can also occur through the mediation of some electrochemically generated redox reagents. Some of them can be present in effluents or added to the solution as an electrolyte to render the solution conductivity. These redox reagents can act as an intermediary for electrons shuttling between the electrode and the organics. These oxidation mediators can be strong oxidizing chemicals, such as active chlorine, ozone, hydrogen peroxide  are efficiently generated only using anodes with high oxygen evolution overpotential, such as boron-doped diamond (BDD) or lead dioxide (PbO2), especially when oxygen is produced as a secondary reaction. The presence of those strong oxidants in wastewater bulk avoids mass-transfer limitation and increases process efficiency [In the case of chlorine, its natural presence or the deliberate addition of Clficiency ,84,85,86−1) together with almost total mineralization and a 91% of phosphate production as final degradation product under the following experimental conditions: sodium chloride medium at 30 mA·cm−2 during 4 h of electrolysis on RuO2 and IrO2 dimensionally stable anode (DSA) electrodes [2/TiO2 coated titanium mesh as both anode and cathode, assisted with MnO2. They reported that glyphosate removal was significantly promoted and most of the released Mn2+ ions were oxidatively reverted to MnO2, which in turn enhanced the removal of glyphosate, allowing 80% of glyphosate degradation after 120 min of treatment at 10 mA cm−2 in 400 mL of solution with sodium sulfate as an electrolyte.In spite of the fact that EO has been identified as one of the cleanest technologies to attain glyphosate removal, there are only a few reports about it. Some of them are analyzed below and summarized in ectrodes . Similarectrodes  studied 3-N and NO3-N. In that way, the authors demonstrated that electro-MnO2 is a better process to mineralize glyphosate from water polluted than only the MnO2 oxidation process. Other authors reported the combination of adsorption over a nano-metal/resin with advanced oxidation for the degradation of a sample of industrial wastewater polluted with 258 mg·L−1 of glyphosate. The maximum degradation rate of glyphosate was enhanced up to 60.5% using only 150 mL of solution in the experimental stage [2) as anode and cathode supplying 100 mA/cm2 of current density during 120 min of treatment time, in a solution with 100 mg·dm−3 of glyphosate and sodium chlorine as support electrolyte to render the solution conductivity and generated chlorine species. Moreover, the authors reported that the achieved efficiency is due to higher concentrations of hydroxyl radicals and hypochlorite in aqueous media which allowed the formation of PO43−, NO3− and CO2 as the main final products of glyphosate mineralization.Additionally, Lan et al.  have proal stage . Recentlal stage  proposed2 electrodeposited on a three-dimensional matrix of reticulated vitreous carbon (RVC) in a flow reactor. They reported that the optimized values of current density, flow rate, and temperature to lead to an improvement of 70% in the mineralization kinetics were 30 mA·cm−2, 3000 mL·min−1, and 50 °C, respectively. Additionally, their study reported the importance of mass transfer in anodic oxidation when a low concentration of organics is present in the effluent, so an increase in flow rate could lead to improve the mineralization kinetics, increase the global current efficiency, and decrease the specific energy consumption. Finally, it is important to mention that the study reported by Oliveira et al. [3 of water, estimating energy consumption of 10–15 kWh·m−3 which corresponds to 3.0–4.5 USD·m−3.In another hand, the study carried out by Oliveira et al.  reporteda et al.  is one oAs can be noticed above, EO could be a promising technology because it lets degrade glyphosate until its total mineralization. Despite that the large-application of EO technology is under development, it has some advantages such as easy operation, environmentally friendly, easy automation, and also could be attractive from an economic point of view because they can use renewable energy from wind and solar sources. However, high cost of electrodes, possibly low conductivity of effluent, electrode fouling, corrosion phenomena, and the possible formation of intermediaries with bigger impact in water ecosystems or human health are some facts that could be considered as disadvantages of process, but also are some challenges to make effort in order to develop a better water treatment technology .a) or constant electric current density (j), and light irradiation (hv) to the photoanode [CB−/hVB+) are generated  [− in the conduction band can return to the h+ in the valence band, dissipating energy in form of electromagnetic radiation or heat, it affects the formation of •OH, which are mostly responsible for the degradation of organic pollutants in aqueous medium [Photoelectrocatalysis (PEC) is an emerging technology that combines photocatalysis with anodic oxidation. It is based on the simultaneous application of either a constant anodic potential  ,91,92. Hs medium .− from the BC and sends them to the cathode. In this way, the recombination of eCB−/hVB+ pairs is avoided and the generation of a greater amount of hBV+ in the semiconductor and the subsequent generation of •OH radicals that mineralize organic matter is encouraged. Additionally, because of the anodic potential applied to the photoanode, the electrons from the BV are easily excited and migrate to the BC, causing photocatalytic reactions can occur even with longer wavelengths (visible light instead of UV). Thus, the PEC improves photoanode efficiency and accelerates the degradation of organic compounds compared to photocatalysis and anodic oxidation when they occur independently [To avoid recombination and consequently improved the degradation of pollutants in water, the anodic potential or constant current density applied to the photoanode continuously extracts the eendently ,91,92. F2CO3, Na2SO4, NaCl) and the applied current density (10–100 mA·cm−2) was studied. Results show that photoelectrocatalysis is more efficient to remove glyphosate because of the formation of higher concentrations of oxidant species formed by photoactivation ions electrogenerated by supporting electrolyte. This process reached the complete mineralization of 100 mg·L−1 of glyphosate (Round-Up) under the following conditions: current density of 100 mA·cm−2, Na2SO4 as support electrolyte, 140 min of treatment time, and Hg vapor UV light lamp (λ = 254 nm) with an intensity of 930 μW·cm−2 [2 is only attained with the DSA® electrode and low power UVC sources (9 W). Complete mineralization of glyphosate was also confirmed by the production of NO3− and PO43− ions close to the stoichiometric amounts as predicted by the theoretical equation. Additionally, energy consumption as low as 1.25 kWh·g−1 was attained [Photoelectrocatalysis has been recently proved to remove glyphosate from water; consequently, a few studies have been reported. The first study was carried out by Rubí-Juárez et al. , who stu μW·cm−2 . The mos μW·cm−2 , who alsattained .As can be noticed, the few studies about photoelectrocatalysis show that it is an effective combined process to mineralize glyphosate in water. However, the studies reported at the current time do not use a photoanode or combine an electrode with photocatalyst but rather are based on radiate an electrode or solution to promote the formation of oxidant species by means of oxidation of ions in electrolytic support. Thus, there is a vast field of research to study PEC to remove organic pollutants in water specifically because PEC is a promising technology that would operate even under solar light, replacing and reducing treatment cost of operation. Finally, is important to mention that PEC is an emerging technology so there are new studies about PEC reactors and photoanode materials applied to remove other organic pollutants principally dyes or phenolic compounds . All of Biological (microorganisms and plants) and physicochemical processes have been combined to treat drinking water and stormwater. Some authors have studied the glyphosate removal efficiency through the adsorption process combined with microorganism degradation in biofilters systems.Melaleuca ericifolia on soil  [Eupatorium perfoliatum, Tradescantia ohiensis, Veronicastrum virginicum, Eragrostis spectabilis, Sorghastrum nutan, Echinacea purpurea on soil  obtained a glyphosate removal efficiency of 99% [Zhang et al.  and Yangil 0.4%) , meanwhiy of 99% . Howevery of 99% . Additioy of 99% . Vegetaty of 99% .ow > 4.5), whereas biodegradation is the main removal mechanism (<20%) of hydrophilic compounds. Moreover, in the biofilter system, the feasibility of biodegradation or sorption depends on support material would fulfill and residence time.Based on results achieved through combined systems , the authors concluded that the removal efficiencies of glyphosate by biofilters could be related to the physicochemical properties of glyphosate. Thus, through biofilters, sorption is the main removal mechanism of lipophilic compounds (K−1 of glyphosate. They found that the maximum degradation rate of glyphosate was enhanced by up to 60% [−1 glyphosate. On the other hand, although the combination of AOPs and biological treatment has been reported as a promised method for wastewater treatment, there is no literature reported for glyphosate degradation by this combined treatment. Oller et al. [Other authors have reported the combination of adsorption with AOPs. Zhang et al.  combinedp to 60% . Xing etp to 60%  combinedr et al.  reportedGlyphosate contamination has emerged as an urgent issue and its negative effects on the environment have attracted considerable attention to develop a variety of treatment processes. The treatment technologies summarized in this review focused on the aqueous medium. Biological treatment can be applied for high amounts of wastewater, and are also low cost and eco-friendly but several operational parameters must be strictly controlled to optimize bioremediation of real water polluted with glyphosate, and in some cases, even a water pretreatment could be required. The adsorption process shows great efficiency at low glyphosate concentration, this process could be a cost-effective solution depending on the elected adsorbate and adsorption competition. However, the main disadvantage of water treatment by adsorption is the residue produced and the not-easy reuse of adsorbents. On the contrary, AOPs are effective to remove glyphosate with a shorter treatment time compared to adsorption and bioremediation. Electrochemical oxidation and photoelectrocatalysis are the cleanest processes and could be used for high glyphosate concentration in wastewater, but some aspects of electrode performance and energy consumption would limit its application. However, these are some challenges to make effort in order to develop better water treatment technology. In the same context, combined processes between AOPs and biological treatment constitute an encouraging technology for glyphosate degradation, but there is limited research. The main purpose of this combination is to increase the biodegradability of the effluent by generating smaller intermediates in the AOPs and the biological treatment would complete the degradation.The degradation mechanism of glyphosate by different treatment processes analyzed in this review show that biological treatment for glyphosate oxidation generally follows two mechanisms related to the cleavage of C-P and C-N bonds attributed to the action of specialized enzymes in biologic organisms as bacterial and fungi species. The difference between bacterial and fungi pathways has been reported by Zhan et al. . SimilarConsidering that the scope of this review is exclusively in an aqueous environment, the most applicable treatment method for glyphosate degradation could be the AOPs. These processes would be the most appropriate treatment method when glyphosate is required to eliminate from an aqueous matrix because AOPs are able to oxidize organic pollutants until its total mineralization. Some studies summarized in this work have reported good degradation efficiencies, it is the case of the work reported by Rubí-Juárez et al. , where 1Finally, there has been some research assessing the degradation of this important herbicide through the different treatment processes. However, the majority of this research has been developed at a laboratory scale using controlled conditions and some of them have employed glyphosate analytic standard, not a commercial herbicide. Therefore, it is necessary to study the applicability of this process in the treatment of real wastewater. Additionally, further research is still necessary in order to know more precise mechanisms during the glyphosate oxidation process and the toxicity of intermediates subproducts. Additionally, an analysis of energetic consumption and operation costs at a real scale is still necessary in order to develop a water treatment technology that allows solving environmental problems, especially in agricultural areas or zones where aerial fumigations of glyphosate persist.


The appropriate and optimal treatment for thoracic and lumbar (TL) burst fractures remains a topic of debate. Characterization of vertical laminar fractures  is presented in this study to determine the severity and treatment options in TL burst fractures.A retrospective evaluation of 341 consecutive patients with TL burst fractures was divided into Group I (whole), Group II , and Group III (intact) based on the vertical laminar fracture morphology from coronal images on computed tomography (CT) scans. The presence of preoperative neurological status was reviewed, and several radiological parameters were measured. In addition, the incidence of dural tears was calculated in patients that underwent a decompression with posterior approach.In total, 270 lumbar and 71 thoracic burst fractures were analyzed. Compared with the intact group, the two other groups had significantly shorter central canal distance, wider interpedicular distance, and smaller spinal canal area, in particular, Group III. The incidences of preoperative neurological deficits in Groups I to III were 63.0, 22.2, and 6.3%, respectively. The incidences of dural tears in Groups I to III were 25.6, 6.3, and 0%, respectively.The morphology of vertical laminar fractures observed across the coronal plane was important. Patients with “whole”, “partial” and “intact” laminar fractures indicated different severity of TL burst fractures. Due to the high probability of dural tears, decompression is recommended as a primary intervention for patients with “whole” laminar fractures. However, for patients without vertical laminar fractures, minimally invasive technique might be a better choice to avoid approach-related complications. Thoracic and lumbar (TL) burst fractures have been reported for several decades . Under aThe correlation between the presence of a laminar fracture and a dural tear as well as between the presence of a dural tear and a severe neurological deficit have been well documented –6. StudiThis study aims to determine the characteristic fracture morphology, preoperative neurological status, and radiological findings of patients with vertical laminar fractures. In addition, the significance of the coronal morphology of laminar fractures is emphasized when choosing the appropriate treatment for TL burst fractures.A total of 341 consecutive patients with acute (within a 10 day history) one level spinal burst fractures  were incGroups used to classify the laminar fracture pattern were: Group I = “whole: whole laminar fracture  or Fisher’s exact test (where appropriate) were used for categorical variables in overall difference statistical analysis. The least significant difference t test (LSD-t) was used for continuous variables and the χ2 partition was used for categorical variables in multiple comparisons. Differences were considered statistically significant at P < 0.05 and the differences were corrected as P < 0.0125 in sections of the χ2 method.The percentages for the widening of the pedicles, compression of anterior vertebral height, narrowing of the central canal distance, and decrease of the spinal canal area in the fractured vertebra were established by comparing the same parameters with those of the vertebrae immediately above and below. The radiological parameters were measured using the Picture Archiving and Communication System  in CT scans. Statistical analysis was performed using IBM SPSS Statistics Version 22 . The analysis of variance was used for continuous variables and the Chi-squared test  followed by simple falls (20.82%), and motor vehicle accidents (9.68%). A total of 71 patients had thoracic fractures and 270 patients had lumbar fractures.P = 0.011), the rest were P < 0.001. In multiple comparisons, the difference among these groups was of great significance based on the ratio of central canal distance, interpedicular distance, and spinal canal area. For the ratio of anterior height, there were no significant differences between groups I and II and between groups I and III. However, the difference between groups I and III was significant . Based on multiple comparisons, the incidences of preoperative neurological deficits in the different groups were significantly different from each other (P < 0.0125).As given in Table In the current study, 105 out of 341 patients underwent decompression with the posterior approach. In groups I to III 20 patients (25.6%), 1 patient (6.3%), and no patients (0%) with dural tears, respectively. A total of 58 patients (74.4%), 15 patients (93.8%), and 11 patients (100%) did not have dural tears, respectively.P < 0.001). The χ2 partition test demonstrated that there was no correlation between groups I and II (P = 0.081), between groups II and III (P = 0.185) with dural tears. However, there was a significant difference between groups I and III (P < 0.001).In Table The laminar fracture was a reliable factor to assess the severity of spinal lesions , 3, whicIt was important to assess the severity (stable or unstable) of spinal fractures for treatment options and avoid neurologic deficits , 8, 10. Denis et al.  noted a In this study, these groups showed significant differences in all the radiological parameters. Except for in anterior height, there were significant differences between Groups I and III in the remaining radiological parameters. Based on the results listed in Tables The preoperative neurological status among these groups was of significant difference. Patients with whole laminar fractures were more probable to be associated with a preoperative neurological deficit than those in the rest groups. In this study, 21 patients had dural tears. The reasons for the presence of posterior dural laceration following vertical laminar fractures might be as follows: (1) the posteriorly displaced dural sac was impaled on the sharp edges of the laminar fracture at the moment of trauma ; and (2)In TL burst fractures, for the treatment of cases with neurological injuries, internal fixation following decompression is widely accepted . HoweverAs with any database study, the limitations of the conclusions in our study must be noted. First, the demographic distributions in each group were various. Both Groups I and III had nearly 45% patients and there were only 36 individuals in Group II. In addition, due to a relative low incidence of such cases described in this study, multicenter studies with larger sample size will be necessary. Anyhow, for the first time, we described the morphology of vertical laminar fractures in TL burst fractures in coronal plane, revealed its association with the severity of spinal injury, and mentioned the significance in choosing the appropriate treatment.Collectively, our study first demonstrates the association of the presence and its types of lamina fractures with posterior dural tear and neurological deficits in traumatic thoracic and lumbar burst fractures.