The seeds germination, stem and root elongation of water lettuces (Lactuca sativa L) were used to evaluate the phytotoxicity of water and soil of Champotón River, Campeche, Mexico. water and soil sample were collected from two sampling sites. Lettuce seeds were exposed to three different dilutions of water and aqueous extract of soil. Significant differences on germination, root and stem elongation of lettuce were detected. Water showed more phytotoxic effect than aqueous extract of soil and inhibitory concentration 50 (IC50) for radicle exposed to river water was 52% while stem elongation was 69%. Due to paucity the previously available phytotoxicological studies onto Champotón River, it is now essential to allocate time and resources to consider development of suitable chronic phytotoxicity tests.

Mangrove forests have proven to be resilient to most environmental change, surviving catastrophic climate events over time. Our study aimed to evaluate the chemical variability of pore water and its effect on phenological production in three mangrove species (Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa) along the coast of the state of Campeche during a year of severe drought (2009) and a year of average precipitation (2010). Pore water salinity and redox potential were measured monthly in a mangrove forest in 2009 and 2010. Litterfall production and reproductive phenology was measured monthly. We determined the relationships among litterfall production, reproductive phenology, pore water chemistry and precipitation of three species between years. Precipitation, pore water salinity and redox potential significantly differed among years, seasons and sites, and also showed significant interaction between years and seasons (p < 0.05). Significant variation was observed in litterfall production, propagules, flowers, and leaf litter among sites (p < 0.05). A significant change was observed in propagules and flowers among years, and in total litterfall and leaf litter between seasons and species (p < 0.05). Under severe drought, salinity had the strongest effect on total litterfall and propagules in R. mangle, while A. germinans, had the strongest effect on propagule/flower precipitation. Both A. germinans and L. racemosa showed higher resilience than R. mangle at all sites under severe drought conditions. These findings can support activity allocation for mangrove conservation and restoration by providing the tolerance thresholds of the three species that dominate in the regional area of Campeche state. Likewise, this research provides knowledge to the Intergovernmental Experts Group on climate change about drought intensity and its magnitude of impact on mangrove productivity, reproduction and integrity.

For decades, mangroves have been exposed to various pressures, resulting in the loss of large swathes around the world. For this reason, ecological restoration actions are presented as alternatives to recover mangroves that can restore their ecosystem services while helping to mitigate climate change’s effects. Mangroves are crucial, as they capture and sequester carbon in biomass and soil, highlighting their importance in environmental conservation and in the fight against climate change. In this research, the amount of carbon sequestered in a mangrove area restored eight years ago and its relationship with soil physicochemical parameters were evaluated and compared to those of a reference forest. Soil cores were collected at a depth of 30 cm from both sites, and in situ measurements of physical chemistry were made at different depths. In addition, soil salinity, bulk density, and carbon concentration were determined. The results revealed a similar amount of carbon sequestered both in the reference forest (BR) (470.17 ± 67.14 Mg C/ha) and in the restoration area (RA) (444.53 ± 86.11 Mg C/ha) (p > 0.05). A direct relationship was observed between carbon sequestration and soil depth. In the case of the RA, a direct relationship was found between carbon sequestration and soil salinity. In conclusion, the results of this study indicate that the behavior of carbon sequestration in soil is determined by the physicochemical conditions in both the BR and the RA, as well as by the presence or absence of vegetation.

The mangrove ecosystem is reported to have a large diversity of species that develop in environments with high salinity levels. Plant species from mangroves are used in traditional medicine and are potential sources of chemicals entities with therapeutic applications. The present work aims to assess and document the influence of salinity on the antioxidant activity exerted by extracts of mangrove species through spectroscopic and chemical analysis. The highest salinity is recorded in Río Verde (RV) in Petén Neyac (PN), an LPBR site. The leaves of Laguncularia racemosa (from RV and PN) recorded the highest extraction yield (35.29 ± 0.45%). Phytochemical analysis indicated the presence of several families of secondary metabolites in the leaves of Rhizophora mangle, Avicennia germinans, and L. racemosa collected in PN and RV, and the chromatographic profile confirms the complexity of the extracts, especially in L. racemosa-RV. The highest content of chlorophylls, carotenoids, and simple phenols was recorded in R. mangle (in RV and PN); flavonoids were high in A. germinans (RV), and the highest antioxidant activity was recorded in L. racemosa (RV) using the DPPH model (EC₅₀: 39.74 ± 0.91 μg/mL; E_max: 67.82 ± 1.00%). According to HPLC, gallic acid (GA), and quercetin (Q) are important metabolites in L. racemosa. FTIR spectra can identify several chemical groups and fingerprint regions in complex mixtures, such as methanolic extracts of the species under study. In this context, this is the first report on chemical changes resulting from species collected at sites with different degrees of salinity. GA is the main metabolite affected by salinity and participates in the antioxidant activity exerted by the original extract, which could explain the physiological adaptations of L. racemosa and its traditional uses. L. racemosa (RV) is ideal for a bioguided phytochemical study that would yield valuable knowledge about its medicinal properties, support ecological conservation, and drive innovation across multiple industries. Further analytical studies are needed to corroborate the impact of salinity on the biosynthesis of secondary metabolites.