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The precipitation variability and trends were investigated in the Usumacinta River Basin (URB) for the period 1959–2018, based on imputed and homogenized data records from 60 meteorological stations in Mexico and Guatemala. The homogenization process played a crucial role in enhancing the quality of the original precipitation series, reducing regional inconsistencies and improving temporal and spatial coherence. The dataset reliably captured large‐scale climate variations, revealing three regions with similar precipitation variability and trends in the URB. Notably, maximum precipitation occurred at 636 m a.s.l., while minimum precipitation was at 1531 m a.s.l., indicating an orographic effect in the region. Extreme precipitation events were linked to El Niño–Southern Oscillation. Although the Mann–Kendall test showed statistically significant negative trends in only 18% of the stations, integration of Sen's slope analysis and 30‐year normals and dry year occurrences highlighted a progressive shift towards dryer conditions throughout the study period in the URB. These drier conditions could notably affect regions with higher precipitation, requiring special attention due to possible socioeconomic impacts associated with drought events. By identifying these vulnerable regions, policymakers and stakeholders can proactively plan and execute adaptive measures to mitigate the potential impacts of droughts on communities, ecosystems, and economic activities within the basin. [ABSTRACT FROM AUTHOR]

The identification and quantification of global change, including climate change, requires long time series of key variables. In this work, the fundamentals and operation of low-cost long-term coastal observatories are described, and preliminary data are shown. The vision is to offer a scientific platform of physicochemical data for at least the next 100 years, what requires establishing sustainable strategies, training human resources, strong institutional support, and long-term funding sources. The network formally operates since 2013 and has generated more than 6 million data points, continuously growing, of which >1.5 million data points are permanently stored and available through a public access web platform. The strategies and methodologies are described and, in the Mazatlan observatory, data recovery and basic statistics of eight environmental variables are presented. During 2015, an extreme El Niño year, marine temperatures increased from the bay to the middle Urias coastal lagoon, were higher than atmospheric temperatures, and showed the impact of a thermal power plant. In surface waters of Mazatlan bay, hypoxic periods were also observed. It is expected that results will foster the development of other projects, and will be useful to the scientific community and decision makers, for a better management of coastal ecosystems worldwide. [ABSTRACT FROM AUTHOR]

To comprehend mangrove crab responses to predicted global climate changes, we assessed submersion and desiccation survival durations and salinity tolerances and upper thermal limits in fiddler crabs from Isla del Carmen, Yucatán Peninsula. Based on their tolerances of extreme ambient conditions, we also calculated safety margins using abiotic monitoring data. The two most terrestrial species, Minuca rapax and Leptuca panacea , exhibited submersion tolerances of from 22 to 40 h, and desiccation tolerances of from 30 to 55 h; LC 50 's were ≈45‰S and UT 50 's were ≈40 °C. The two least terrestrial species, M. vocator and L. speciosa , were less tolerant of all experimental challenges, showing submersion and desiccation tolerances of <6 h, and LC 50 's of 36‰S and UT 50 's of 38 °C. While these fiddler crabs inhabit niches closer to their salinity and desiccation/submersion tolerances than to their temperature limits, all are clearly vulnerable to the multiple stressors that accompany anticipated global climate change. [Display omitted] • Four species of Yucatan fiddler crabs were challenged by multiple environmental stressors. • Lethal exposure times ranged from 22 to 40 h for submersion, and 30 to 55 h for desiccation. • No species tolerated salinities above 50‰S; the upper critical thermal limits were ≈40 °C. • All species were within their safety margins for temperature but not for salinity and desiccation/submersion. • Fiddler crabs are clearly vulnerable to the multiple stressors that accompany predicted global climate change. [ABSTRACT FROM AUTHOR]

Intertidal ecosystems, such as marshes, mangroves, and seagrasses, contribute to the global carbon storage, helping to regulate atmospheric CO 2 concentrations. Organic carbon (C org) data from seagrass meadows in the Mexican coastline are still scarce, preventing appropriate evaluations of its contribution to mitigate global climate change. Recent temporal changes (≤100 years) of C org concentrations and burial rates were assessed in 210Pb dated cores from seagrass meadows at Terminos Lagoon, the largest coastal lagoon in the southern Gulf of Mexico. Irrespective of the predominant seagrass species, the cores showed comparable C org concentrations (0.04–3.9%) and burial rates (2.5 – 66.7 g m−2 yr−1). Increasing salinization, likely caused by sea level rise, favoured C org concentrations and burial rates in sediments with Halodule wrightii , while in sediments with Thalassia testudinum only C org burial rates increased, owing to increasing mass accumulation rates, likely promoted by erosion induced by land use changes, and sea level rise. The mean C org stock (1 m depth; 130 ± 29 Mg ha−1) was comparable with the global average C org stock for seagrasses in other tropical areas around the world. Our results suggested that, under the current scenario of land use change and marine transgression, the seagrass meadows in Terminos Lagoon preserve the capacity for C org accumulation and long-term preservation. However, both factors are also known to reduce seagrass resilience caused by water quality deterioration, thus these ecosystems must be monitored and protected from global change impacts, as part of climate change mitigation efforts. Image 1 • C org burial rates and stocks were studied in seagrass meadows from Terminos Lagoon. • 210Pb-dated sediment cores showed C org stocks accumulated during at least 100 years. • Salinity likely enhanced C org sediment storage in a Halodule wrightii seagrass meadow. • C org burial rates were enhanced by increasing sediment accumulation rates. [ABSTRACT FROM AUTHOR]