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Despite their ability to mitigate climate change by efficiently absorbing atmospheric carbon dioxide (CO2) and acting as natural long-term carbon sinks, mangrove ecosystems have faced several anthropogenic threats over the past century, resulting in a decline in the global mangrove cover. By using standardized methods and the most recent Bayesian tracer mixing models MixSIAR, this study aimed to quantify source contributions, burial rates, and stocks of organic carbon (Corg) and explore their temporal changes (∼100 years) in seven lead-210 dated sediment cores collected from three contrasting Mexican mangrove areas. The spatial variation in Corg burial rates and stocks in these blue carbon ecosystems primarily depended on the influence of local rivers, which controlled Corg sources and fluxes within the mangrove areas. The Corg burial rates in the cores ranged from 66 ± 16 to 400 ± 40 g m-2 yr-1. The Corg stocks ranged from 84.9 ± 0.7 to 255 ± 2 Mg ha-1 at 50 cm depth and from 137 ± 2 to 241 ± 4 Mg ha-1 at 1 m depth. The highest Corg burial rates and stocks were observed in cores from the carbonate platform of Yucatan and in cores with reduced river influence and high mangrove detritus inputs, in contrast to patterns identified from global databases. Over the past century, the rising trends in Corg burial rates and stocks in the study sites were primarily driven by enhanced inputs of fluvial-derived Corg and, in some cores, mangrove-derived Corg. Despite their decreasing extension, mangrove areas remained highly effective producers and sinks of Corg. Ongoing efforts to enhance the global database should continue, including mangrove area characteristics and reliable timescales to facilitate cross-comparison among studies.

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Remote sensing data and numerical simulation are important tools to rebuild any oil spill accident letting to identify its source and trajectory. Through these tools was identified an oil spill that affected Oaxacan coast in October 2022. The SAR images were processed with a standard method included in SNAP software, and the numerical simulation was made using Lagrangian transport model included in GNOME software. With the combining of these tools was possible to discriminate the look-alikes from true oil slicks; which are the main issue when satellite images are used. Obtained results showed that 4.3m3 of crude oil were released into the ocean from a punctual point of oil pollution. This oil spill was classified such as a small oil spill. The marine currents and weathering processes were the main drivers that controlled the crude oil displacement and its dispersion. It was estimated in GNOME that 1.6 m3 of crude oil was floating on the sea (37.2 %), 2.4 m3 was evaporated into the atmosphere (55.8 %) and 0.3 m3 reached the coast of Oaxaca (7 %). This event affected 82 km of coastline, but the most important touristic areas as well as turtle nesting zones were not affected by this small crude oil spill. Results indicated that the marine-gas-pump number 3 in Salina Cruz, Oaxaca, is a punctual point of oil pollution in the Southern Mexican Pacific Ocean. Further work is needed to assess the economic and ecological damage to Oaxacan coast caused by this small oil spill.

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Globally, oxygen concentration in many coastal areas is depleting. River nutrient discharges may produce hypoxia events. The Southern Gulf of Mexico receives the discharges of the Grijalva-Usumacinta River System, the second largest in the Gulf of Mexico. To evaluate the influence of river discharges on dissolved oxygen concentrations in the receiving coastal ecosystem, we studied the variation of physicochemical variables in the water column. During the dry season, the influence of the river waters to the coastal area is scarce, but during the rainy season the river plume reached ~9 km offshore. The lowest concentration of dissolved oxygen (3.6 mg L-1) was observed within the river plume. We concluded that, in the studied area, hypoxia events (oxygen concentrations ≤ 2 mg L-1) would occur during the rainy season, low winds and in deeper waters (>80 m depth).

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The development of the Grijalva-Usumacinta river basin exerts modifications on its discharge area. A sediment core was studied to reconstruct environmental changes and trace element contamination status during the past 45 years. 210Pb-derived mass accumulation rates indicate higher sediment input to the area since 1995, related to increased precipitation and floodings in the catchment area. Sediments show finer particles from the late 1970s on, likely related to dams construction upriver and/or land use changes. Heavy metal enrichment factors (EF < 2) suggest minimum contamination. Benthic foraminifera and redox-sensitive - elements (As, Ba, Co, Cr, Cu, Ni, Pb, V and Zn) indicate the sediments before 2000 were deposited under oxygenated conditions. Afterwards, environmental conditions changed and benthic foraminifera and dinocysts assemblages changed suggesting eutrophication and lower oxygen conditions during the last 20 years. Monitoring should be continued to assess eutrophication/hypoxic/pollution trends that could become deleterious to the marine biota.

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Studies on age and growth in fishes are essential to establish models on population dynamics. The previous issues were determined in this study by scale growth analyses. Between September 2003 and May 2004, 382 organisms were captured using gill and atarraya nets. Eight samples were developed every month a long this study. Standard length in centimeters (L(e)), total weight in grams (P9t)), scale length in centimeters (L(esc)) and growth rings were determined. The size and weight ranged from 38 to 232 mm (L(e)) and 8.7 to 311.9 g (P(t)), respectively. The growth rings analyses reveal four age groups, being the second group the most representative with 34.3% of the total sampled. The scale ring analyses showed two growth rings, one develops between November-January and the other between April-May, in good correlation with low temperature and gonad development, respectively. The growth parameters were established as: L infinity = 281.1mm, W infinity = 877.1g, K = 0.33 and T(0) = 0.88 year(-1). The growth curves based on length and weight were described by using the von Bertalanffy model: L(e) = 28.11[1 -e (-0.33(t+0.88))] and P(t) = 877.17[1-e (-0.33(t+0.88))]3. Finally, it is concluded that commercial catches in this dam are between a year and year and half-old when exploited.

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Age and growth of the hybrid tilapia Oreochromis niloticus x Oreochromis aureus (Perciformes: Cichlidae) in the dam “Zimapan” Mexico. Studies on age and growth in fishes are essential to establish models on population dynamics. The previos issues were determined in this study by scale growth analyses. Between September 2003 and May 2004, 382 organisms were captured using gill and atarraya nets. Eight samples were developed every month a long this study. Standard length in centimeters (Le), total weight in grams (Pt), scale length in centimeters (Lesc) and growth rings were determined. The size and weight ranged from 38 to 232mm (Le) and 8.7 to 311.9g (Pt), respectively. The growth rings analyses reveal four age groups, being the sec-ond group the most representative with 34.3% of the total sampled. The scale ring analyses showed two growth rings, one develops between November-January and the other between April-May, in good correlation with low temperature and gonad development, respectively. The growth parameters were established as: L∞=281.1mm, W∞=877.1g, K=0.33 and T0=0.88year -1. The growth curves based on length and weight were described by using the von Bertalanffy model: Le =28.11[1-e-0.33(t+0.88)] and Pt =877.17[1-e-0.33(t+0.88)]³. Finally, it is concluded that commercial catches in this dam are between a year and year and half-old when exploited. Rev. Biol. Trop. 59 (2): 761-770. Epub 2011 June 01.

La edad y crecimiento de la tilapia Oreochromis niloticus x Oreochromis aureus fueron determinados por medio de la lectura de escamas. Un total de 382 individuos fueron capturados mediante el uso de redes agalleras y atarrayas. Ocho recolectas mensuales se llevaron a cabo entre septiembre 2003-mayo 2004; se registraron los datos de longitud estándar en cm. (Le), el peso total en g (Pt) y se obtuvieron muestras de escamas para registrar el largo de la escama en mm. (Lesc) y el número de anillos de crecimiento formados. Las tallas y pesos de recolecta variaron entre 38 a 232mm (Le) y de 8.7 a 311.9g de peso total (Pt) respectivamente. El recuento de los anillos anuales en escamas, permitió establecer cuatro grupos de edad, siendo el grupo de edad 2 el más representativo, con un 34.3% de la población muestreada. El cálculo de los incrementos marginales del crecimiento mensual de las escamas, sugirió la formación de dos anillos, uno de ellos se forma en los meses de noviembre-enero y otro en los meses de abril-mayo, los cuales coinciden con la época de bajas temperaturas y de madurez gonádica respectivamente. Los parámetros de crecimiento quedaron establecidos en: L∞=281.1mm, W∞=877.1g, K=0.33 y T0=0.88/año. Las curvas de crecimiento en longitud y peso se describieron mediante las ecuaciones de von Bertalanffy: Le=28.11 [1- e-0.33(t+0.88)] y Pt=877.17 [1-e-0.33(t+0.88)]³. Finalmente, se concluyó que los peces que se explotan en la represa mediante captura comercial presentan entre un año y año y medio de edad.

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The objective of this study was to analyse the prevalence and characteristics of the main clinical and immunological manifestations at the onset and during the evolution of the disease in a cohort of patients from Latin America (mainly of mestizo origin) and to compare the Latin American with the European patients. Clinical and serological characteristics of 100 APS patients from Mexico and Ecuador were collected in a protocol form that was identical to that used to study the ;Euro-Phospholipid' cohort. The cohort consisted of 93 female patients (93.0%) and seven (7.0%) male patients. There were 91 mestizos (91.0%), seven whites (7.0%) and two Amerindians (2.0%). The most common manifestations were livedo reticularis (40.0%), migraine (35.0%), inferior extremity deep vein thrombosis (32.0%), thrombocytopenia (28.0%) and hemolytic anemia (20.0%). Several clinical manifestations were more prevalent in Latin American than in European patients and they included mainly neurological (migraine, transient global amnesia, acute ischemic encephalopathy, amaurosis fugax) and cutaneous (livedo reticularis, skin ulcerations, superficial cutaneous necrosis, multiple subungual splinter hemorrhages) manifestations as well as hemolytic anemia. The APS has a wide variety of clinical and immunological manifestations at the onset and during the evolution of the disease and the ethnic origin in addition to environmental and socioeconomic factors can modify the disease expression.

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