Abstract
Introduction:
Coral reefs of Guadeloupe have undergone substantial ecological degradation over the past decade, driven by cumulative disturbances including mass bleaching events, the emergence of Stony Coral Tissue Loss Disease (SCTLD), repeated Diadema antillarum die-offs and recurrent cyclones.
Methods:
A 10-year dataset (2014-2024), from the European Water Framework Directive, combining physicochemical measurements, benthic composition and herbivorous fish census, was used to assess the changes in the overall health status of 14 coral reefs located around Guadeloupe (Lesser Antilles).
Results:
Results show that benthic communities had already shifted toward algal dominance prior to the monitoring period, but that coral decline has accelerated markedly after 2020 in response to major environmental crises. Multivariate analyses identify turbidity, nutrient enrichment and chlorophyll concentrations as the primary drivers of benthic differentiation, with eutrophicated sites exhibiting high macroalgal cover and reduced coral recruitment. In contrast, reefs exposed to clearer oceanic waters maintained higher proportions of calcifying organisms and diversified herbivore assemblages. Spatial variability therefore reflects the interplay between regional disturbances and site-specific hydrological conditions.
Conclusion:
These findings underscore the increasing vulnerability of Guadeloupean reefs and highlight the need to reduce land-based nutrient inputs, improve wastewater management, and preserve herbivore communities to sustain the remaining coral communities and their ecological functions.
Highlights
Key calcifiers have declined sharply between 2020 and 2024.
Site-level conditions shape divergent ecological trajectories.
Herbivore biomass is higher at sites with better water quality.
Nutrients inputs drive macroalgal dominance across exposed reefs.
Findings highlight priorities for coastal nutrient management.
1 Introduction
The phenomenon of eutrophication has now spread worldwide, with major consequences for the balance of aquatic ecosystems (; ; Tomascik and Sander, 1987). Increased nutrient inputs promote opportunistic algal blooms on reefs, leading to competition between corals and macroalgae for space and light, resulting in a deterioration of the reef structure. This weakening reduces refuge opportunities for associated communities, including herbivorous organisms, whose presence is essential for regulating algal biomass (; McManus, 2000; McManus and Polsenberg, 2004). Moreover, once macroalgae are well established and grow to a considerable size, herbivorous fishes and urchins are no longer able to consume and regulate them (). There are many sources of mineral pollution that can lead to eutrophication, from agricultural fertilizers to coastal urbanization, but wastewater discharge constitutes the main source of nitrogen enrichment (; Lapointe and Clark, 1992). In coral reefs, this mineral pollution is also positively correlated with the occurrence of coral diseases and epizootics, which promote widespread reef degradation (; Yoshioka et al., 2016; ).
All these disturbance factors are conducive to the coral-algal phase shift phenomenon, characterized by the replacement of coral communities by the establishment of macroalgae on the reef (). In tropical environments, coral reefs are particularly sensitive to variations in water physicochemical parameters, notably acidification, salinity and oxygenation, but also to overfishing (Leitão et al., 2023; Kekuewa et al., 2021). These factors, in interaction with anthropogenic and climatic pressures, directly influence the growth and resilience of benthic communities and fish populations.
This study was conducted in Guadeloupe, an archipelago of approximately 163500 ha located in the Caribbean. Guadeloupe faces cumulative sources of pollution, due to global environmental changes and human activities (; Lesueur Jannoyer et al., 2016; ; Wilkinson and Souter, 2008). Among these pressures, poor wastewater management represents a major issue. In 2022, 56% of wastewater treatment plants of <2000 population equivalent (PE) were deemed non-compliant (Office de l’eau, 2024). The declared rainwater collection network is non-existent, therefore, rivers are generally the receptacles of runoff water. Improvements to the stormwater collection infrastructure are underway, however it is possible that, due to poor network connections, stormwater may be heavily contaminated (Office de l’eau, 2021). Furthermore, agricultural practices still rely heavily on the use of pesticides and other chemical substances. According to the latest assessments, 55% of coastal water bodies are classified as being in poor ecological status, while the remaining 45% are considered to be in only moderate condition.
The coral reefs of Guadeloupe have been impacted by several acute and chronic stressors over recent decades. Chronic pressures include declining water quality associated with nutrient enrichment, terrestrial runoff, and wastewater discharge, as well as reductions in key herbivore populations. These pressures have been compounded by acute disturbances such as mass bleaching events in 2005, 2019, 2023, and 2024, the emergence of Stony Coral Tissue Loss Disease (SCTLD) in 2020, and epizootic outbreaks affecting the sea urchin Diadema antillarum, a key herbivorous species, in 1983 and 2022 (Malahel et al., 2023; ; Lessios, 2016, Lessios, 1988).
Among the initiatives for monitoring aquatic ecosystems, the Water Framework Directive (WFD) provides a European regulatory framework for assessing the ecological and chemical status of surface and groundwater. In Guadeloupe, the WFD is managed by the Office de l’Eau, and its assessment grids have been adapted to the tropical context since 2007. Monitoring has thus been set up in coastal water bodies (18 sites) and rivers (39 stations), with execution ensured by various consultancies. Ecological status is assessed on the basis of biological (aquatic invertebrates and diatoms), physicochemical and specific pollutant data, while chemical status is based on the analysis of 45 hazardous and priority substances, in accordance with the national decree of July 27, 2015. As part of this study, herbivorous fish were monitored to supplement the database.
This study describes a 10-year temporal monitoring integrating physicochemical parameters, benthic composition collected from the WFD database, as well as herbivore richness and abundance data. The main objective was to determine whether variations in benthic community composition, and in particular coral cover, can be explained by environmental conditions such as nutrient enrichment and by the structure of herbivorous communities. More broadly, the study examines whether seawater physicochemical parameters influence benthic composition and whether this composition is related to the dynamics of herbivorous fishes and sea urchins in a tropical island context.
2 Methods
2.1 Study site
Guadeloupe is an archipelago located in the heart of the arc of the Lesser Antilles, comprising five islands, four of which are inhabited. Monitoring was carried out on the main island, the largest and most populous, as well as on Les Saintes and Désirade (Figure 1). In 2021, Guadeloupe had around 384300 inhabitants, including around 2500 at Les Saintes and 1400 at Désirade (). Monitoring was carried out on 14 sites, including 11 distributed around Guadeloupe, two in Les Saintes and one at Désirade, in water depths of 10–15 m (Figure 1). Monitoring has been in place since 2009 as part of the Water Framework Directive, an initiative to monitor the status of European coastal water bodies. For the purposes of this article, only data from 2014 to 2024 were processed. Monitoring was not conducted in 2015 due to administrative delays.
Figure 1
2.2 Hydrological and physico-chemical parameters
Water samples were taken between the surface and 0.5 meters deep, using a Niskin bottle, and immediately stored in a cool place at a temperature below 4 °C. To ensure reliable analysis, water used for nutrient measurements was filtered immediately upon collection through a 10-µm filter attached directly to the outlet of the Niskin bottle, thereby removing particles that could alter nutrient measurements. The concentrations of chlorophyll and dissolved inorganic nutrients, including phosphate (PO43-), ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-), were determined from these samples by external laboratories. Although analytical laboratories varied throughout the monitoring period, all analyses followed the continuous-flow colorimetric methods recommended by Aminot and Kérouel (2004, 2007). Laboratories were selected based on their ability to provide quantification limits suitable for the oligotrophic conditions typical of Guadeloupean coastal waters. Depending on the laboratory and period, quantification limits ranged from 0.01 to 0.10 µM for ammonium, 0.03 to 0.05 µM for nitrite, 0.02 to 0.05 µM for phosphate, and 0.05 to 0.20 µM for nitrate + nitrite.
Hydrological and physicochemical parameters were sampled up to six times per year at most coastal water sites. At Caye à Dupont, Gros Cap, and Rocroy, sampling has been carried out on a monthly basis since 2016. In 2014, all sites were sampled every two months. Regarding physicochemical parameters, temperature (°C) and salinity (PSU) were measured by a multi-parameter probe (NKE, WiMo). The probe was returned annually to the manufacturer for calibration.
2.3 Benthic community monitoring
Benthic community monitoring was carried out on reef areas. The census was conducted along six permanent 10-m-long transects positioned at the same isobath to ensure consistency in data collection. Transects were established in 2014 within homogeneous reef areas considered representative of each site. Their positions were permanently marked using galvanized stakes and steel rods placed every 10 m and maintained during each annual survey. The nature of the benthic community was characterized by a Point-Intercept Transect (PIT) method, along the six transects with a record of the substrate and the benthic organisms present every 20 cm. Each point was coded according to the categories defined in the national BD-Recif database. This protocol makes it possible to quantify the diversity and abundance of the populations of corals, macroalgae, cyanophyceae and algal turf. Species were identified to genus or species level whenever possible. The total sampling effort was 300 points per station, that is 50 points per transect.
Juvenile coral (<2 cm in width) densities were assessed within a 0.5m wide belt transect along the same benthic transect. A 50 cm PVC tube was used to standardize the measurement. The sampling effort represented a total surface area of 30 m2 of reef per station.
Along each 10-m transect, coral colonies, necrosis, diseases, and bleaching occurrences were recorded within a 1-m-wide belt transect positioned adjacent to the line. The total sampling effort therefore covered 60 m2 per station (6 transects × 10 m × 1 m). This benthic monitoring was carried out once a year between May and June, and coral bleaching and tissue necrosis have been monitored since 2019. A single colony could be affected by more than one pathology simultaneously, and each condition was recorded independently.
2.4 Stock assessment of grazing echinoderms and herbivorous fish
The sea urchin census was conducted on a 1-meter-wide strip along the six transects deployed. Sea urchins were identified and counted. The sampling effort covers a total surface area of 60 m2 per station. For the purpose of the present study, only Diadema antillarum was included in the dataset due to its grazing capacity on coral reefs. As part of the WFD protocol, the echinoderm monitoring was carried out once a year between May and June, at the same time as the benthic monitoring.
In parallel, at each site, three transects of 60 meters long were deployed close to the transects dedicated to the benthic composition census. Along each transect, all herbivorous fishes observed within a 5 m wide corridor (2.5 m on either side of the transect line; total surveyed area = 300 m2 per transect) were identified and counted. Herbivorous fishes included species belonging to the families Acanthuridae, Scaridae, and Pomacentridae. Species were assigned to four functional guilds according to their feeding strategy, including browser (feeding primarily on fleshy macroalgae), scraper (removing epilithic algae while scraping the substrate surface), excavator (removing portions of carbonate substrate while feeding), and territorial farmer (damselfishes cultivating and defending algal lawns) (see Supplementary Table 1 for the complete list of species and guild assignments).
Each transect was surveyed in approximately 5 min by a diver swimming at a consistent pace, ensuring standardized sampling effort among sites. The size of each individual was estimated and classified into one of nine pre-selected size classes (0–5 cm, 6–10 cm, 11–15 cm, 16–20 cm, 21–25 cm, 26–30 cm, 31–35 cm, 36–40 cm, and >40 cm). Fish biomass was estimated using species-specific length-weight relationships of the form W= aLb, where W is body mass (g), L is fish length (cm), and a and b are species-specific coefficients obtained from FishBase (). For each size class, the midpoint of the interval was used as the representative fish length (2.5, 8, 13, 18, 23, 28, 33, 38 and 45 cm, respectively). Biomass values were subsequently standardized to g·100 m-2 to allow comparisons among sites.
Only the site Pointe des Colibris (PDC) was the subject of only two transects, as the small surface reef area did not allow the deployment of a third line. The herbivorous fishes survey has been added for the present study and was only conducted in June 2024.
2.5 Statistical processing
The databases from the WFD were sorted and filtered to retain only the results from 2014 onwards. All analyses were performed to characterize the spatio-temporal dynamics of benthic composition and to assess relationships between benthic communities, environmental parameters and herbivore communities. Temporal trends in the main benthic functional groups were explored using non-parametric Spearman correlation tests, allowing the detection of significant increases or decreases in coverage over the study period. Relationships between benthic variables and environmental parameters were quantified using Pearson correlations, highlighting the trophic gradients structuring community composition.
In order to assess interannual changes in the benthic composition, Friedman tests (rank analysis) were applied to all sites, supplemented by Nemeyi’s post hoc tests to identify the groups responsible for the differences observed. These analyses were also used to specifically compare years, highlighting temporal breaks associated with episodes of major disturbance.
Multivariate patterns were explored using Partial Triadic Analysis (PTA), to characterize the common structure between sites and years. Similarities between tables were evaluated using the RV coefficient, which measures the correlation between two multivariate datasets and quantifies their structural similarity. The αk weights, derived from the interstructure analysis, were used to determine the relative contribution of each site to the overall compromise, that is, to the common structure shared across years. The quality of representation of each site in the factorial space was measured by the coefficients of determination (cos²). Hierarchical clustering (Ward’s method) was applied to the standardized benthic composition matrix in order to identify groups of sites sharing similar ecological profiles. We did not convert the matrix into a distance structure prior to clustering, as this procedure distorts the ecological meaning of the data and leads to groups driven by geometric artifacts rather than biological patterns. The classification therefore represents ecological similarity based on benthic assemblages, which is consistent with the objective of identifying spatial patterns within the PTA framework. A Principal Component Analysis (PCA) was performed to explore the covariations between hydrological parameters and benthic composition. The projection of the variables onto the correlation circle allowed the visualization of the dominant environmental gradients and their influence on benthic groups.
To assess the strength of associations between hydrological parameters and benthic assemblages, Pearson’s correlation coefficients (r) were computed. Significant correlations (p< 0.05) were used to highlight environmental drivers potentially influencing the structure of benthic communities. To explore the relationships among hydrological parameters, benthic composition, and herbivorous fish assemblages (expressed as biomass), a Principal Component Analysis (PCA) was performed using data collected in 2024. The first two principal components explaining most of the variance were retained for interpretation. Variable grouping (hydrological, benthic, and herbivorous) allowed the identification of ecological gradients and potential associations between compartments. To quantify the strength and direction of these associations, Pearson correlation coefficients (r) were computed, using pairwise complete observations. The significance of correlations was assessed at p< 0.05.
All analyses were conducted using R (R Core Team), with packages dedicated to multivariate statistics and graphical visualization.
3 Results
3.1 Benthic composition monitoring from 2014 to 2024
Temporal analysis of the main benthic functional groups highlighted notable changes during the study period. Spearman’s correlation tests revealed significant changes in several community compartments. Significant increases were observed in macroalgae (p = 0.01) and cyanophyceae (p = 0.002), reflecting an increase in non-building organisms at the expense of reef building stony corals. Conversely, hard corals showed a significant negative trend (p < 0.001), indicating a progressive loss of coral cover (Figure 2). Detailed site-specific temporal trends in benthic composition are provided in Supplementary Figure 1.
Figure 2
Rank analysis using the Friedman test confirmed the existence of a significant change in overall benthic composition (p<0.001). The post hoc test identified macroalgae (both calcareous and fleshy) and algal turf, in contrast with crustose calcareous algae and hard corals as the main groups responsible for the observed interannual heterogeneity. These results suggested a dynamic of reef degradation, marked by a gradual substitution of reef-building corals by opportunistic taxa. The Friedman test applied across years (p= 0.102) did not reveal any significant interannual differences in overall benthic composition. This means that, statistically, no specific year stands out as having a markedly different benthic structure. While visual trends (e.g., gradual shifts in coral or algal cover) may be apparent, these changes are not strong enough to be considered significant in a non-parametric framework.
The average temperature recorded during the May-June benthic monitoring surveys showed interannual fluctuations consistent with regional patterns. A maximum was measured in 2016 (28.5 °C), while the lowest average temperature was observed in 2018 (27.1 °C). These values correspond specifically to the period during which benthic surveys were conducted. Temperature was monitored throughout the year as part of the hydrochemical sampling campaigns, and annual trends are presented in Supplementary Figure 2. Although the May-June measurements do not cover the warmest months of the year, when marine heatwaves typically occur (July-September), they provide a standardized snapshot of thermal conditions during the benthic monitoring period.
3.2 Health status of coral colonies (necrosis, bleaching) 2019–2024
Analysis of coral health data revealed occasional episodes of physiological stress. Between 2019 and 2024, most coral colonies monitored showed no signs of bleaching. In 2019, 8.3% of colonies (n= 7/84) exhibited partial bleaching (1-50%). In 2020, 2.9% of colonies (n= 14/491) were affected, including three colonies that were fully bleached (91-100%). From 2021 to 2024, bleaching prevalence decreased markedly, with only isolated cases observed each year (≤4.6% of colonies). Overall, these data suggest that bleaching remained relatively limited along the PIT transects. However, these observations likely underestimate the full extent of thermal stress impacts because surveys were conducted before the seasonal temperature peak, when mass bleaching events typically occur. Severe bleaching episodes were nevertheless documented elsewhere across the Guadeloupe archipelago during the same study years (Figure 3A).
Figure 3
Patterns of necrosis revealed more pronounced and sustained impacts on coral colonies compared to bleaching. In 2019, 69.4% of colonies (n = 68/98) exhibited partial or extensive tissue loss, with five colonies completely necrosed (91-100%). The peak occurred in 2020, with 45.1% of colonies (n= 230/510) showing necrosis, including 9 colonies entirely affected. Although prevalence decreased after 2020, necrosis remained consistently present. 11.3% of colonies in 2021, 35% in 2022, 33.2% in 2023, and 37.3% in 2024 showed partial to extensive tissue loss. Notably, severe cases (≥51% surface necrosed) were detected every year after 2019, with up to 12 colonies per year completely necrosed. These results suggest a chronic and recurrent impact of coral tissue necrosis on Guadeloupean reefs, consistent with the emergence and spread of SCTLD during this period (Figure 3B). Site-specific patterns of bleaching and necrosis prevalence are presented in Supplementary Figures 3, S4.
Monitoring of coral recruitment showed a marked peak in 2019. This peak was observed at Ti Pâté (409 recruitments) and Gros Cap (263 recruitments). Lower recruitment values were subsequently recorded at all sites from 2020 onwards, indicating a reduction in the natural renewal potential of coral populations (Full site-specific data are available in Supplementary Table 2).
3.3 Spatial variation in herbivorous fish biomass (2024)
Mean total fish biomass varied markedly among sites, ranging from only 21 ± 1.7 g·100 m-2 at Anse Bertrand to 1004 ± 386 g·100 m-2 at Gros Cap (Figure 4). The highest biomasses were observed at Gros Cap, Pointe Lezarde (654 ± 253 g·100 m-2), and Ti Pate (585 ± 261 g·100 m-2), while Main Jaune, Rocroy, Tête à l’Anglais, and Ilet Fajou showed intermediate values (253–441 g·100 m-2). Lower biomasses were recorded at Caye à Dupont, Pointe des Mangles, Capesterre, Pointe des Colibris, Ilet Gosier, and Ilet Kahouanne (85–235 g·100 m-2). The lowest biomass was observed at Anse Bertrand (21 ± 1.7 g·100 m-2).
Figure 4
Across all sites, scrapers were the dominant functional guild, contributing on average 67% of the total biomass, and exceeding 80% at Main Jaune (82.3%), Pointe Lezarde (92.9%), and Ilet Fajou (87.0%). Browsers were the second most important group (up to 60.7% at Gros Cap and 45.8% at Pointe des Colibris), whereas territorial farmers and excavators generally accounted for less than 10% of total biomass. Excavators were absent from five sites (Anse Bertrand, Capesterre, Gros Cap, Ilet Gosier, Ilet Kahouanne), while browsers were missing from four sites (Anse Bertrand, Ilet Fajou, Pointe des Mangles, Tête à l’Anglais).
Functionally, scrapers were ubiquitous, detected at all 14 sites, whereas browsers and territorial farmers were present at 10 and 12 sites each. Excavators were present at 8 sites.
3.4 Influence of environmental parameters on benthic composition
The interstructure analysis conducted using Partial Triadic Analysis (PTA) made it possible to characterize the similarities between the different benthic data tables from the study sites (Table 1). The RV coefficient matrix, which measures the proximity of the tables’ structures, revealed variable similarity values between sites. The highest values were observed between Rocroy and Gros Cap (RV = 0.82), indicating comparable benthic structure between these two sites. Equally high similarities were found between Pointe des Mangles and Capesterre (RV = 0.73) and between Caye à Dupont and Capesterre (RV = 0.72). Conversely, the lowest RV values, such as those between Ilet Fajou and Ilet Gosier (RV = 0.29), suggested highly differentiated, or even atypical, data structures compared to the other sites.
Table 1
| k | AB | C | CAD | GC | IF | IG | IK | MJ | PDC | PDM | R | PL | TAA | TP | αk | cos2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AB | 1 | 0.22 | 0.32 | |||||||||||||
| C | 0.29 | 1 | 0.28 | 0.72 | ||||||||||||
| CAD | 0.35 | 0.72 | 1 | 0.28 | 0.70 | |||||||||||
| GC | 0.54 | 0.58 | 0.64 | 1 | 0.32 | 0.78 | ||||||||||
| IF | 0.56 | 0.38 | 0.27 | 0.41 | 1 | 0.22 | 0.36 | |||||||||
| IG | 0.31 | 0.59 | 0.59 | 0.70 | 0.24 | 1 | 0.27 | 0.65 | ||||||||
| IK | 0.40 | 0.53 | 0.63 | 0.63 | 0.34 | 0.55 | 1 | 0.28 | 0.74 | |||||||
| MJ | 0.45 | 0.50 | 0.54 | 0.54 | 0.56 | 0.43 | 0.43 | 1 | 0.25 | 0.58 | ||||||
| PDC | 0.41 | 0.52 | 0.62 | 0.61 | 0.36 | 0.48 | 0.47 | 0.46 | 1 | 0.27 | 0.63 | |||||
| PDM | 0.29 | 0.73 | 0.53 | 0.47 | 0.49 | 0.50 | 0.43 | 0.43 | 0.49 | 1 | 0.26 | 0.58 | ||||
| R | 0.53 | 0.51 | 0.61 | 0.82 | 0.35 | 0.55 | 0.66 | 0.31 | 0.54 | 0.36 | 1 | 0.29 | 0.69 | |||
| PL | 0.46 | 0.50 | 0.48 | 0.60 | 0.38 | 0.55 | 0.60 | 0.39 | 0.59 | 0.60 | 0.60 | 1 | 0.28 | 0.62 | ||
| TAA | 0.34 | 0.36 | 0.40 | 0.55 | 0.40 | 0.41 | 0.53 | 0.46 | 0.50 | 0.52 | 0.50 | 0.43 | 1 | 0.25 | 0.56 | |
| TP | 0.32 | 0.43 | 0.38 | 0.59 | 0.47 | 0.57 | 0.42 | 0.50 | 0.52 | 0.42 | 0.56 | 0.49 | 0.55 | 1 | 0.26 | 0.52 |
Numerical parameters associated with partial triadic analysis of biological data.
RV, matrix of vector correlation coefficients between tables; αk, weighting indicating the contribution of each table K to the construction of the compromise; cos2, cosine squared between table K and the compromise reduced to its interpreted part (along two axes); AB, Anse Bertrand; C, Capesterre; CAD, Caye à Dupont; GC, Gros Cap; IF, Ilet Fajou; IG, Ilet Gosier; IK, Ilet Kahouanne; MJ, Main Jaune; PDC, Pointe des Colibris; PDM, Pointe des Mangles; R, Rocroy; PL, Pointe Lézarde; TAA, Tête à l’Anglais; TP, Ti Pâté.
Analysis of the αk weights, which reflect the relative influence of each site in the construction of the compromise, highlighted the strong contribution of Rocroy and Gros Cap (αk = 0.29; αk = 0.32). These two sites thus appear to be the most decisive in defining the common structure. In contrast, Ilet Fajou and Anse Bertrand, with a relatively low weight (αk = 0.22 each), contribute less to the overall compromise. This low contribution may reflect a specific or atypical benthic organization at these sites.
Examination of the coefficients of determination (cos²) made it possible to assess the quality of the representation of individual tables in the compromise. Gros Cap stands out for its excellent representation quality (cos² = 0.78), reflecting a good fit between its data and the overall structure. In contrast, Anse Bertrand exhibits a more modest quality (cos² = 0.32), suggesting that this site only partially shares the structure highlighted at the regional level.
Diagonalization of the vector covariance matrix (RV) identified the principal axes, whose decreasing eigenvalues reflect the inertia captured by each. The first axis extracts a substantial portion of the total variance (7.43, or 53.1%), while the second explains 8.4% (1.17). The projection of the sites in the space defined by the first two axes highlights the formation of four ecologically distinct groups, confirmed by Ward’s hierarchical ascending classification (Figure 5). These groups reflect ecological proximities in the benthic composition of the sites.
Figure 5
The analysis of the compromise, which synthesizes information from the various tables into a weighted average representation, highlights marked temporal and ecological trends in the benthic composition of the study sites (Figure 6). The factorial plan defined by the first two axes of the compromise reveals a clear opposition between different sampling periods, reflecting profound changes in the structure of benthic communities over the decade studied.
Figure 6
Thus, recent years (2022-2024) fall within an area of the plan characterized by a strong association with cyanophyceae and macroalgae. These opportunistic groups appear to have colonized and rapidly invaded available substrates, reflecting a recolonization dynamic typical of environments subject to disturbance. Conversely, the period from 2014 to 2016 is marked by a dominance of turf algae, corresponding to low (< 3 cm), dense, and largely indistinct algal assemblages typical of algal turfs. Between 2016 and 2020, the compromise highlights a strong presence of live corals. The position of these years in the plan suggests a period when indicators of healthy reefs were particularly dominant.
Principal Component Analysis (PCA) was performed to characterize the influence of environmental parameters on benthic composition within the two largest ecological clusters identified by hierarchical clustering of benthic assemblages. These clusters represented reefs sharing similar benthic community structures and ecological trajectories over the study period. This approach allowed the exploration of covariation patterns between hydrological variables and benthic taxa while accounting for the ecological specificities of each cluster (Figure 7). Only clusters 1 and 2 were retained for PCA analyses because they encompassed the majority of study sites, whereas clusters 3 and 4 included only two and one sites, respectively, preventing robust multivariate interpretation.
Figure 7
For this first group, the first two axes explain 20.5% (Dim1) and 15.6% (Dim2) of the total inertia (Figure 7A). The first axis (Dim1) is strongly structured by the hydrological parameters CHLOROC1.C2 (chlorophyll c1 + c2), CHLOROC3 (chlorophyll c3), and CHLOROA (chlorophyll a), indicators of phytoplankton biomass, as well as turbidity (TURB.FNU), all positively correlated with this dimension. In terms of benthic life, Dim1 is positively correlated with the presence of calcifying macroalgae and encrusting algae, suggesting that these sites offer favorable conditions for the development of opportunistic taxa in moderate eutrophication and high productivity environments. The Pearson correlation analysis supports these patterns, showing significant positive relationships between variables indicative of productivity (e.g., turbidity, chlorophyll concentrations) and calcareous algal cover (TURB.FNU vs. calcareous macroalgae: r= 0.545, p< 0.001; TURB.FNU vs. encrusting calcareous algae: r= 0.381, p = 0.0016).
In contrast, Dim2 distinguishes sites characterized by variations in dissolved nutrient concentrations and salinity. This axis is positively associated with ammonium (NH4), nitrite (NO2), nitrate (NO3.NO2), and phosphate (PO4), and negatively with salinity (SALI), indicating a gradient of nutrient enrichment potentially linked to freshwater inputs or terrestrial runoff. From a benthic perspective, sites scoring higher on Dim2 tend to show lower coral cover and a reduced presence of encrusting calcareous algae, consistent with the influence of nutrient enrichment on benthic community structure. The Pearson correlation analysis supports these patterns, with salinity negatively correlated with nutrient concentrations (SALI vs. NH4: r = -0.291, p = 0.018; SALI vs. NO2: r = -0.314, p = 0.010; SALI vs. PO4: r = -0.246, p = 0.046). Conversely, a positive correlation between nitrite and hard corals (NO2 vs. hard corals: r = 0.435, p < 0.001) suggests that coral assemblages may persist under moderate nutrient levels but decline under more pronounced eutrophic conditions. Overall, Dim2 reflects a nutrient and salinity gradient that further structures benthic communities, where increased nutrient loading tends to favor algal development at the expense of calcifying organisms.
In the second group, the first two axes explain 25.8% (Dim1) and 20.1% (Dim2) of the total inertia (Figure 7B). The first axis (Dim1) is structured by CHLOROA (chlorophyll a), CHLOROC1.C2 (chlorophyll c1 + c2), and FLORTOT (total phytoplankton cell abundance), the latter corresponding to microphytoplankton assemblages (> 20 µm) quantified by microscopic counts, as well as by benthic variables such as calcareous and fleshy macroalgae, all positively correlated with this dimension. In contrast, hard corals and algal turf show negative loadings, indicating their predominance in less productive environments. Pearson’s correlation analysis supports these patterns, revealing significant positive relationships between CHLOROA and calcareous macroalgae (r= 0.539, p = 0.0026), and between CHLOROC1.C2 and fleshy macroalgae (r= 0.376, p = 0.0445).
The second axis (Dim2) contrasts nutrient and turbidity enriched sites (high NH4, NO3.NO2, PO4, and TURB.FNU) with more saline and stable environments. A strong negative relationship between salinity and both phosphate (r= -0.536, p = 0.0027) and turbidity (r= -0.531, p = 0.0030) highlights the influence of terrigenous inputs. Similarly, encrusting calcareous algae are negatively correlated with turbidity (r= -0.436, p = 0.0181).
These results revealed a marked influence of hydrological parameters on the structuring of benthic communities in both groups of sites. Turbidity, phytoplankton biomass (chlorophyll concentrations), and nutrient levels emerge as key structuring variables, being consistently associated with higher macroalgal cover and increased representation of opportunistic taxa at the most disturbed sites. Conversely, more stable and oligotrophic hydrological conditions appeared to be associated with benthic communities dominated by building corals.
3.5 Interactions between benthic composition, environmental parameters and herbivore abundance
To further examine the relationships between herbivorous fish assemblages and benthic composition under the 2024 hydrological conditions, a Principal Component Analysis (PCA) was conducted on the combined dataset including hydrochemical, benthic, and herbivore (abundance) variables (Figure 8). The first two components accounted for 39.7% of the total variance (Dim.1 = 21.0%; Dim.2 = 18.7%).
Figure 8
The first axis (Dim.1) was strongly correlated with the abundance of territorial and grazing herbivores such as Stegastes leucostictus (r= 0.93), Scarus vetula (r= 0.88), and Stegastes planifrons (r= 0.84). These species were positively associated with hard coral cover (r= 0.55) and encrusting calcareous algae (r= 0.47), indicating that sites supporting higher densities of key herbivores also maintained greater proportions of calcifying benthic organisms. Conversely, Acanthurus tractus (r= -0.57) and Acanthurus chirurgus (r= -0.32) were negatively correlated with this axis, suggesting their prevalence in more turbid or nutrient-enriched areas where turf algae were abundant (turf algal cover, r= -0.60; salinity, r= -0.73). Pearson correlations confirmed that turbidity (TURB.FNU) and nitrate concentrations (NO3+NO2) were positively related (r= 0.66) and both inversely linked to coral cover (r= -0.46), reinforcing the idea that eutrophic conditions are associated with reduced coral and herbivore richness.
The second axis (Dim.2) was characterized by high positive loadings for turbidity (r= 0.78), nitrite (r= 0.67), and nitrate (r= 0.77), and negative loadings for several benthic and herbivore variables, notably Acanthurus coeruleus (r= -0.55), Sparisoma aurofrenatum (r = -0.66), and Stegastes adustus (r= 0.67). This axis thus captured a nutrient and suspended-matter gradient, contrasting turbid, nitrogen-rich sites with clearer areas dominated by calcifying macroalgae (r = 0.79) and territorial damselfishes. The negative correlations between nitrate levels and macroalgal groups (r = -0.35) indicate that high nutrient inputs favor non-calcifying algal proliferation, potentially reducing available grazing substrates for specialized herbivores.
Together, these results highlight a strong coupling between herbivore community structure and the hydrological-benthic context. Sites characterized by high coral and calcareous algal cover tended to support higher abundances of both territorial (Stegastes spp.) and scraping parrotfishes (Scarus spp.), whose positive associations (r= 0.8) with coral cover suggested their functional contribution to maintaining coral-dominated states. In contrast, nutrient-enriched and turbid environments positively associated with turf algae and negatively correlated with coral cover (r= -0.46), supported fewer specialized herbivores and a greater dominance of opportunistic species.
4 Discussion
4.1 Environmental perturbations and community shifts
Over the 2014–2024 monitoring period across 14 reef sites in Guadeloupe, our results reveal pronounced ecological changes reflecting the cumulative impact of regional and local disturbances. The intervening period 2018–2022 appears to be a transitional phase marked by major environmental disturbances, including marine heatwaves, mass bleaching events, the emergence of Stony Coral Tissue Loss Disease (SCTLD), epizootic of Diadema antillarum, and high-intensity cyclones. In addition, recurrent Sargassum strandings recorded in Guadeloupe over the past decade may have contributed locally to hypoxic conditions and nutrient enrichment in nearshore environments, although their specific influence was not explicitly assessed in the present study. These events seem to have contributed to a profound reorganization of benthic communities, favoring the expansion of opportunistic groups (cyanophyceae, algae) at the expense of reef-building corals and organisms indicative of healthy reefs.
The trends highlight the progressive establishment of algal communities at the expense of corals, whose cover has declined sharply. Between 2014 and 2024, coral cover decreased by 60.5%, while soft macroalgae cover increased by 43.5%. The decline, visible as early as 2020, is consistent with the environmental disturbances that occurred during this period, notably the emergence of SCTLD, first observed in Guadeloupe in 2020, six years after its initial detection in Virginia Key, Florida (Precht et al., 2016). Stony Coral Tissue Loss Disease is considered the most lethal Scleractinian disease described to date, responsible for massive losses in Western Atlantic reefs and affecting nearly 30 coral species (; Muller et al., 2020).
In 2020, 45.1% of monitored coral colonies exhibited partial or total necrosis attributed to SCTLD. This irreversible disease has led to significant mortality in species key to the structure and function of Caribbean reefs. In Florida, for example, mortality rates ranging from 17% to 81% depending on the species of Scleractinian coral have been reported (; Precht et al., 2016), as well as 46% in Cozumel () and approximately 30% in the Dominican Republic ().
At the same time, a mass mortality event affecting Diadema antillarum occurred in 2022, likely caused by a scuticociliate pathogen, resulting in the loss of a key reef grazer (; ). Estimates indicate a loss of more than 50% of the population (; Levitan et al., 2023; Villalpando et al., 2022), which is less than during the first epizootic in the 1980s, when 93-98% of individuals disappeared, leading to an increase in algal biomass of between 20% and 439% (Lessios, 2016; , ). This crisis was followed by a widespread decline in coral cover and encrusting algae in favor of macroalgae and turf algae on many Caribbean reefs (; ; ). As part of this monitoring, a 96.7% decline in the D. antillarum population was observed between 2021 and 2023.
In addition, Guadeloupe experienced marine heatwaves (above 29 °C) in 2016 and then in 2023-2024, causing large-scale coral bleaching. According to other local monitoring studies, 95% of coral species and 50-80% of colonies were affected by the 2023 bleaching event, followed by mortality rates of 29% to 60% the following year (). As the hottest periods extend from July to September, the monitoring carried out in June did not capture the extreme temperature peaks or their immediate effects on the reefs.
Another disruptive factor is the passage of cyclones, which generate cyclonic swells that cause mechanical damage (uprooting of sponges and gorgonians, destruction of branching colonies). In 2014, 2017, and 2024, cyclones of categories 4, 5, and 4 respectively affected Guadeloupe. However, the monitoring time window (May-June) did not allow for the observation of direct damage at the stations studied, as the cyclone season extends from July to November.
The increase in algal coverage intensifies competition between algae and corals for access to the substrate, which is reflected in the results with a negative trend in coral recruitment from 2019 onwards, falling from 1601 recruits across all sites to only 210 recruits in 2024. Similar patterns have been observed in other studies in Guadeloupe, which also report a marked decline in recruitment in 2024 (; ). In general, larval recruitment of bioconstructing corals is hampered by the proliferation of opportunistic taxa (Webster et al., 2015; Kuffner et al., 2006). The 141% increase in cyanobacteria is consistent with the release of substrate following coral mortality due to disease or destruction caused by cyclonic swells. These organisms frequently colonize recently dead corals (; ).
Despite these disturbances and the coral-algal phase shift clearly visible in the trends over the decade studied, the changes observed are not sufficient to conclude that there has been a significant change in benthic composition over the years. The periods during which the various disturbance events occurred correspond to the phases revealed by our analyses. A stable period from 2014 to 2018 characterized by the dominance of turf algae and structuring coral communities, a phase-shift from 2018 to 2022, followed by a marked establishment of opportunistic taxa (macroalgae and cyanophyceae) between 2022 and 2024.
4.2 Influence of hydrological parameters on benthic composition
4.2.1 Role of eutrophication and the triptych of nutrients, turbidity, and phytoplankton
Analyses show that turbidity, chlorophyll concentrations, and dissolved nutrient availability are the main factors explaining the differentiation of benthic communities. In the first group of sites, axis 1 of the PCA is dominated by parameters reflecting pelagic productivity (chlorophyll a, C1/C2, C3) and turbidity. This gradient is strongly associated with an increase in calcareous and encrusting macroalgae, indicating that the most productive environments favor the expansion of opportunistic organisms typical of mesotrophic to eutrophic conditions. These results are consistent with the mechanisms described in the literature, where eutrophication leads to reduced light, increased algal biomass, and decreased competitive success of corals (Lesser, 2021; ; ; ; Lapointe, 1997).
The second group of sites reveals a similar structure. Environments with the highest nutrient and phytoplankton concentrations consistently exhibit a greater representation of fleshy or calcareous macroalgae, while coral assemblages dominate only in the clearest and most stable waters. This convergence between groups suggests that the processes responsible for the transitions to algal states are generalized across all the monitored reefs. The temporal trends emerging from the compromise confirm this trajectory. The period 2016-2020, characterized by a strong coral presence, is gradually being replaced, starting in 2022, by a marked dominance of cyanobacteria and macroalgae, a pattern regularly observed on Caribbean reefs in response to chronic increases in nutrients, turbidity, or SCTLD (Swaminathan et al., 2024; Quezada-Perez et al., 2023; Zamoner et al., 2021).
4.2.2 Salinity gradients and terrigenous inputs
Salinity also plays a structuring role, particularly through its close link with dissolved nutrients and turbidity. The negative correlations observed between salinity and phosphate or ammonium indicate dilution of the water column by terrigenous inputs from runoff, wastewater treatment plant effluents, or river plumes. These intrusions of fresh water, often rich in particles and nutrients, favor opportunistic macroalgae at the expense of corals and calcareous algae, whose physiological performance is impaired by osmotic stress and reduced light availability (; ). Sites located under the direct influence of watersheds, notably Capesterre, Pointe des Mangles, and Caye à Dupont, have a profile characterized by high turbidity, significant terrigenous input, high concentrations of dissolved nutrients, and a low proportion of calcifiers. In addition to these diffuse pressures, there is the specific case of Anse Bertrand, whose benthic dynamics appear to be strongly influenced by the proximity of a wastewater treatment plant outfall. According to the latest report from the Water Authorities of Guadeloupe (Office de l’eau, 2024), this plant had several episodes of non-compliance between 2017 and 2022, with documented exceedances in 2017, 2019, and 2021. These insufficiently treated discharges constitute a recurring and persistent source of nutrients and suspended matter, likely to exacerbate local eutrophication and contribute to the low dominance of calcifying organisms observed at this site. Conversely, sites exposed to more open marine circulation, such as Gros Cap, Ti Pâté, and Pointe Lézarde, exhibit more stable physico-chemical conditions, a smaller terrigenous footprint, and greater preservation of reef-building organisms.
4.2.3 Ecogeographical interpretation: identification of sites most subject to terrigenic pressures
The combination of multivariate approaches (PTA, PCA, and hierarchical clustering) allows for a more detailed distinction between the spatial and temporal structures of the reefs studied. The RV coefficients indicate consistent and similar temporal profiles between sites such as Rocroy and Gros Cap, suggesting relative stability in their benthic composition over the decade. Conversely, Capesterre, Caye à Dupont, and Pointe des Mangles also have high RV values between them, but their common dynamic corresponds to a gradual shift toward more algal states, consistent with the intensification of terrigenous pressures. Ward’s classification, based exclusively on the similarity of average benthic composition between sites, confirms this spatial organization. The sites most influenced by terrigenous inputs, notably Capesterre and Pointe des Mangles, are grouped together due to their high turbidity, more variable salinities, and the predominance of opportunistic macroalgae. In contrast, Gros Cap appears to be one of the most stable sites, characterized by a strong representation in the PTA compromise (cos²= 0.78), indicating that its average benthic structure particularly well reflects the regional trend. These results indicate that Gros Cap has characteristics of stability and low eutrophication that would make it a potential candidate for reference monitoring.
Some sites, such as Ilet Fajou and Anse Bertrand, have lower contributions to the compromise, indicating that their benthic structure diverges significantly from the regional trend. However, the mechanisms underlying this singularity differ from site to site. Ilet Fajou, located in the heart of a semi-enclosed bay and relatively far from the coastline (5km-8km), receives diffuse terrigenous inputs but remains partially isolated from the direct influences of watersheds. Its location within the National Park also reduces direct anthropogenic pressures, which can lead to unique benthic dynamics that are sometimes out of sync with the regional signal. Meanwhile, Anse Bertrand is heavily influenced by anthropogenic terrestrial inputs from a wastewater treatment plant outlet, whose history of non-compliance (Office de l’eau, 2024) suggests recurrent nutrient inputs.
The isolation of these sites within the regional structure resulting from the PTA highlights that, despite a general trend toward eutrophication in several areas, a significant portion of benthic variability remains governed by local processes. This coexistence of regional signals and site-specific dynamics constitutes a frequent pattern in reef systems subjected to spatial gradients of exposure, protection and terrigenous pressures ().
4.3 Environmental drivers of herbivore biomass
The results showed strong spatial variability in herbivorous fish biomass among the studied sites, reflecting the heterogeneity of local conditions and recent changes in the ecological trajectories of the reefs. The highest biomasses were observed at Gros Cap, Pointe Lézarde, and Ti Pâté, while sites such as Anse Bertrand and Capesterre showed significantly lower values. This contrasting distribution highlights that, despite common regional pressures, some reefs retain a greater capacity to maintain functionally diverse herbivore communities to adulthood, consistent with greater coral and calcareous algae cover (Sura et al., 2025; Morales-de-Anda et al., 2024; Olán-González et al., 2023).
Scrapers largely dominate the communities (67% of the total biomass) and are present at all sites. Their ubiquitous presence reflects their functional importance in controlling epilithic algae and facilitating coral recruitment, processes documented in numerous reef systems (Mumby et al., 2007; ). Browsers, although less ubiquitous, represent a significant proportion of biomass at some sites (up to 60.7% at Gros Cap), indicating sufficient availability of macroalgae or conditions that support specialized species such as Acanthurus tractus or large Sparisoma. Conversely, the absence of excavators at nearly half of the stations could reflect either a degraded reef structure or historical fishing pressure on these vulnerable species, as observed in many Caribbean regions ().
Multivariate analyses confirm that the structure of herbivore communities is closely linked to hydrological quality and benthic composition. The first PCA axis shows that sites with high coral cover and abundant calcareous algae are associated with high biomasses of scrapers and territorial farmers (Stegastes spp.), as well as Scarus vetula, a key species for maintaining a substrate conducive to coral recruitment (Adam et al., 2018; Steneck et al., 2014). The strong positive correlations between these species and coral cover (r> 0.5) indicate a functional coupling where diverse herbivore communities contribute to maintaining the dominance of calcifying organisms, but also benefit from the structured habitats that the latter provide.
Conversely, sites characterized by high turbidity and nitrate concentrations (i.e., indicators of eutrophication) showed increased dominance of fleshy algae and turf, associated with reduced biomasses of specialized herbivores. The negative correlation between turbidity, nitrates, and coral cover (r = -0.46) highlights that nutrient-enriched conditions favor the transition to states dominated by opportunistic algae. In these environments, species such as Acanthurus tractus or A. chirurgus, which are more tolerant of degraded conditions, become more prevalent. This pattern is consistent with observations made in other tropical regions, where nutrient and sediment gradients alter the composition of herbivore communities and increase the risk of a shift to an algal regime (; ).
The negative relationships observed between nitrate concentrations and calcifying algae cover also indicate that terrigenous inputs may reduce the availability of substrates favorable to scrapers, thereby limiting their ecological effectiveness. Taken together, these results support the idea that herbivore communities play a central role in reef resilience, but that their structure is strongly constrained by hydrological conditions affecting benthic status. Sites combining better water quality, a high proportion of calcifying organisms, and high herbivore biomass thus appear to be refuge areas, capable of resisting biophysical disturbances more effectively (; ; Muthukrishnan et al., 2016).
In the Guadeloupean context, marked by a decade of cumulative stress (heat waves, SCTLD disease, mass D. antillarum mortalities, cyclones), these results illustrated the variable capacity of sites to maintain functional links between herbivores and benthic ecosystems. They also highlighted the importance of herbivores as indicators and mediators of ecological trajectories. The absence or low abundance of excavators and browsers in some reefs, combined with the increasing dominance of non-calcifying algae, could accelerate the transition to macroalgal-dominated states if these dysfunctions persist.
5 Conclusion
This 10-year assessment of Guadeloupe’s coral reefs reveals a system already engaged in a long-term transition toward algal dominance. The relative stability of benthic communities during the early years of monitoring (2014-2018) suggests that the establishment of opportunistic taxa began well before the study period. However, the sharp decline of reef-building corals and calcifying algae observed since 2020 reflects an acceleration of degradation linked to cumulative disturbances, including mass bleaching events, the emergence of SCTLD, repeated Diadema antillarum die-offs, and the influence of major cyclones. Hydrological parameters proved to be the primary drivers of benthic structure. Sites characterized by high turbidity, nutrient enrichment and terrigenous inputs, often associated with watershed runoff or wastewater discharge, showed a consistent shift toward fleshy and calcifying macroalgae, accompanied by reduced coral cover and weakened recruitment. Conversely, reefs exposed to clearer, more stable oceanic waters maintained higher proportions of calcifiers and showed greater ecological stability. These spatial contrasts highlight that, despite regional-scale disturbances, local hydrological conditions remain a key factor shaping reef trajectories. Herbivorous fishes also played a central role in these dynamics. Higher biomasses of scrapers and browsers were recorded at sites with better water quality and more structured benthic communities, supporting their contribution to substrate maintenance and coral recruitment. In contrast, degraded sites displayed reduced functional diversity and increased dominance of generalist herbivores, reflecting a weakening of ecological feedbacks essential for resisting algal expansion. Together, these results indicate that Guadeloupean reefs are undergoing a pronounced and potentially irreversible ecological shift, yet their trajectories remain heterogeneous. Continued long-term monitoring will be critical for determining whether these systems stabilize in a macroalgal state, continue to decline, or show signs of recovery, potentially through the emergence of more tolerant coral species. Strengthening the management of wastewater, reducing terrigenous inputs and preserving herbivore communities constitute essential levers for mitigating eutrophication and sustaining the last resilient reef areas of the archipelago.
Statements
Data availability statement
The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.
Ethics statement
The manuscript presents research on animals that do not require ethical approval for their study.
Author contributions
H-MM: Investigation, Conceptualization, Data curation, Formal analysis, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing. CB: Investigation, Supervision, Validation, Writing – review & editing. PC: Supervision, Validation, Writing – review & editing. CD: Investigation, Supervision, Validation, Writing – review & editing.
Funding
The author(s) declared that financial support was not received for this work and/or its publication.
Acknowledgments
The authors gratefully acknowledge support from the Région Guadeloupe and the Office de l’Eau Guadeloupe.
Conflict of interest
The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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Supplementary material
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmars.2026.1870701/full#supplementary-material
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Summary
Keywords
Caribbean, coastal pollution, coral-algal phase-shift, long-term monitoring, nutrients inputs
Citation
Malahel H-M, Batailler C, Claquin P and Dromard CR (2026) A decade of coral reef monitoring in Guadeloupe (Lesser Antilles). Front. Mar. Sci. 13:1870701. doi: 10.3389/fmars.2026.1870701
Received
01 May 2026
Revised
26 June 2026
Accepted
01 July 2026
Published
20 July 2026
Volume
13 - 2026
Edited by
Aarón Israel Muñiz-Castillo, Healthy Reefs for Healthy People, Mexico
Reviewed by
Tyler Burton Smith, University of the Virgin Islands, US Virgin Islands
Laëtitia Mathon, Nature Foundation, Sint Maarten
Updates
Copyright
© 2026 Malahel, Batailler, Claquin and Dromard.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Hanna-May Malahel, hannamay.malahel@gmail.com
Disclaimer
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