Spatial variability of dissolved nickel is enhanced by mesoscale dynamics in the Gulf of Mexico

The Gulf of Mexico (GoM) is one of the most dynamic marginal seas in the world owing to the intrusion of the Loop Current and the shedding of anticyclonic eddies (LCE) that travel westward across the Gulf. However, the impacts of these mesoscale dynamics on the supply and removal of bioessential trace metals in surface waters remain unclear. We study the impact of mesoscale eddies on the distribution of dissolved nickel (Ni), a biologically active element scarcely studied in the region. The vertical distribution of Ni was determined in the deep-water region of the GoM during summer of 2017, when two anticyclonic LCE (Quantum and Poseidon) were present. Nutrient-like profiles of Ni in the GoM resemble those from the Atlantic Ocean, but they showed high spatial variability within the first 1000 m, which was associated with the impact of mesoscale eddies. Similarly to subtropical gyres, macronutrients were almost depleted in surface waters, while Ni never fell below 1.51 nmol kg-1, suggesting low Ni lability or alternatively, slow biological uptake compared to that of macronutrients. In particular, lowest levels of Ni and macronutrients (PO4 and NO3) were recorded in surface waters of the anticyclonic eddies and the Loop Current area. Anticyclonic LCEs deepened these Ni-poor waters pushing the Ni-rich core of Tropical Atlantic Central Water up to 600 m, whereas its shallowest position (up to 200 m) was recorded under cyclonic conditions in Campeche Bay. This eddy-induced vertical displacement of water masses also affected the integrated Ni and macronutrient concentrations in the upper 350 m but without modifying their stoichiometries. We suggest that a significant decrease in surface inventories of Ni and macronutrient in areas impacted by LCEs is a consequence of the trapping of the water within eddies, the biological uptake of Ni and macronutrients combined with their limited replenishment from below, which likely affects autotrophic groups. In conclusion, the mesoscale dynamic permanently present in the GoM play an important role in modifying the vertical distribution of Ni and macronutrients as well as their availability in the upper water column of this marginal sea

Data base of Atmospheric inputs of iron and manganese to coastal waters of the southern California Current System: Seasonality, Santa Ana Winds, and biogeochemical implications

<p>These data were used in a manuscript recently submited to Journal of Geophysical Research-Oceans: </p><p> Félix-Bermúdez A., F. Delgadillo-Hinojosa, M.A. Huerta-Diaz, V. Camacho-Ibar and V. Torres-Delgado (2017), Atmospheric inputs of iron and manganese to coastal waters of the southern California Current System: Seasonality, Santa Ana Winds, and biogeochemical implications.</p> <p>The dataset consists of:</p><p>1) Five-year time series: </p> <p>>Atmospheric mineral dust flux (Fdust) . <br> >Total concentrations of iron (Fe), manganese (Mn) and aluminum (Al) in dust particles. <br> >Total atmospheric fluxes of Fe (FFe), Mn (FMn) and Al (FAl). <br> >Enrichment factors and percentages of non-lithogenic contribution <br> >Monthly average of meteorological data (pressure, relative humidity, wind speed and direction, and total rainfall) recorded in CICESE's Observatory (<a href="http://observatorio.cicese.mx/cicese/Current_cicese.htm/">http://observatorio.cicese.mx/cicese/Current_cicese.htm/</a>).<br> <br> 2) Experiments under Santa Ana Wind conditions: <br> >Atmospheric mineral dust flux (Fdust) . <br> >Total concentrations of iron (Fe), manganese (Mn) and aluminum (Al) in dust particles. <br> >Total atmospheric fluxes of Fe (FFe), Mn (FMn) and Al (FAl). <br> >Enrichment factors and percentages of non-lithogenic contribution <br> >Monthly average of meteorological data (pressure, relative humidity, wind speed and direction, and total rainfall) recorded in CICESE's Observatory (<a href="http://observatorio.cicese.mx/cicese/Current_cicese.htm/">http://observatorio.cicese.mx/cicese/Current_cicese.htm/</a>).</p> <p> <br></p

Composición y biomasa fitoplanctónica bajo condiciones oligotróficas en la cuenca de Guaymas (golfo de California)

Con el propósito de determinar la biomasa y la composición del fitoplancton (picofitoplancton, nanodiatomeas y microdiatomeas) bajo condiciones oligotróficas, se realizó un estudio en la capa superficial de la cuenca de Guaymas, golfo de California, durante el verano tardío de 2016. El estudio contempló la medición de variables hidrográficas, químicas y biológicas en la capa superficial del área de estudio. Nuestros resultados mostraron una columna de agua cálida, fuertemente estratificada, empobrecida en nutrientes y con biomasas fitoplanctónicas reducidas (<1 mg Cla·m–3). Los cocientes promedio de N:P (0.55 ± 1.34), N:Si (0.13 ± 0.18) y Fe:N (52.70 ± 29.70) indicaron condiciones de limitación por N. La contribución de los grupos fitoplanctónicos a la biomasa fluctuó ampliamente por nivel de profundidad, y se observó  el predominio del picofitoplancton (85.0 ± 2.7%) en superficie (5 m) y de las nano-microdiatomeas (91.5 ± 5.9%) en el nivel más profundo (35-40 m), adyacente a la termoclina. Las diatomeas dominaron la biomasa integrada entre la superficie y 50 m de profundidad, con una contribución promedio ~6 veces mayor que la del picofitoplancton. A pesar de que se registraron condiciones ideales para la proliferación de cianobacterias diazótrofas, la presencia de Trichodesmium spp. y Richelia intracellularis fue muy irregular y en abundancias relativamente bajas (2,220 ± 1,575 célula·L–1). Nuestros resultados son especialmente relevantes, ya que sugieren que, bajo condiciones de limitación por N, el paradigma de la alta biomasa y dominancia de células grandes en el golfo de California puede verse desafiado durante la temporada de verano

Dysbiotic changes of periodontal pathogens in patients wearing conventional and self-ligating orthodontic appliances

Objective: This study aimed to analyse dysbiotic changes of periodontal pathogenic bacteria and their relationship with different types of fixed orthodontic appliances in a population located in Northwestern Mexico