Here we developed a composite pollen-based record of altitudinal vegetation changes from Lake Fúquene (5° N) in Colombia at 2540 m elevation. We quantitatively calibrated Arboreal Pollen percentages (AP%) into mean annual temperature (MAT) changes with an unprecedented ~60-year resolution over the past 284 000 years. An age model for the AP% record was constructed using frequency analysis in the depth domain and tuning of the distinct obliquity-related variations to the latest marine oxygen isotope stacked record. The reconstructed MAT record largely concurs with the ~100 and 41-kyr (obliquity) paced glacial cycles and is superimposed by extreme changes of up to 7 to 10° Celsius within a few hundred years at the major glacial terminations and during marine isotope stage 3, suggesting an unprecedented North Atlantic – equatorial link. Using intermediate complexity transient climate modelling experiments, we demonstrate that ice volume and greenhouse gasses are the major forcing agents causing the orbital-related MAT changes, while direct precession-induced insolation changes had no significant impact on the high mountain vegetation during the last two glacial cycles

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Tropical montane biome migration patterns in the northern Andes are found to be coupled to glacial-induced mean annual temperature (MAT) changes; however, the accuracy and resolution of current records are insufficient to fully explore their magnitude and rates of change. Here we present a ~60-year resolution pollen record over the past 284 000 years from Lake Fúquene (5° N) in Colombia. This record shows rapid and extreme MAT changes at 2540 m elevation of up to 10 ± 2 °C within a few hundred of years that concur with the ~100 and 41-kyr (obliquity) paced glacial cycles and North Atlantic abrupt climatic events as documented in ice cores and marine sediments. Using transient climate modelling experiments we demonstrate that insolation-controlled ice volume and greenhouse gasses are the major forcing agents causing the orbital MAT changes, but that the model simulations significantly underestimate changes in lapse rates and local hydrology and vegetation feedbacks within the studied region due to its low spatial resolution

Para completar el diágnóstico de la calidad ambiental en el Parque Marino Nacional Isla Mujeres-Cancún-Nizuc Caribe mexicano, se estudió la posible utilidad de la criptofauna: de rocas como monitora de impacto. Se trazó un transecto a lo largo de un gradiente de intensidad de visitantes a Punta Nizuc. Se visitaron tres lugares (1.5-4 m proO, a 50, 250 Y 500 m de distancia de la plataforma turistica, y en cada uno de ellos se recogieron tres rocas. Los 1368 organismos encontrados fueron identificados y se distribuyen en 2 18 especies; los grupos de mayor riqueza específica fueron los poliquetos (64 spp), los moluscos (46 spp) y los crustáceos (36 spp). Se estudió la variación en número y en biomasa a lo largo del supuesto gradiente ambiental, y también la relación de algunos descriptores de la comunidad (diversidad, dominancia) con la distancia a la plataforma, con la densidad de la roca y con la profundidad. Se analizaron algunos índices que utilizan 10glO(biomasa + 1) y las curvas de abundancia-biomasa para determinar la calidad del ambiente. Se realizaron análisis de agrupamiento (Bray-Curtis y Jaccard) para determinar la afinidad entre estaciones. Para evaluar la funciorialidad de la suficiencia taxonómica en fondos coralinos, se compararon los resultados de dominancia de Berger-Parker para las especies y familias. Las agrupaciones entre las rocas ilustran dos grupos principales, uno formado por las rocas recolectadas cerca de la plataforma (zona perturbada) y la otra formada por el resto de las rocas en las áreas con mediano y nulo impacto.