Pelagic Sargassum in the Gulf of Mexico driven by ocean currents and eddies.

Pelagic Sargassum in the Gulf of Mexico (GoM) plays an important role in ocean biology and ecology, yet our knowledge of its origins and transport pathways is limited. Here, using satellite observations of Sargassum areal density and ocean surface currents between 2000 and 2023, we show that large amounts of Sargassum in the GoM can either originate from the northwestern GoM or be a result of physical transport from the northwestern Caribbean Sea, both with specific transport pathways. Sargassum of the northwestern GoM can be transported to the eastern GoM by ocean currents and eddies, eventually entering the Sargasso Sea.

Naturally acquired antibodies against Plasmodium vivax pre-erythrocytic stage vaccine antigens inhibit sporozoite invasion of human hepatocytes in vitro.

In Plasmodium vivax, the most studied vaccine antigens are aimed at blocking merozoite invasion of erythrocytes and disease development. Very few studies have evaluated pre-erythrocytic (PE) stage antigens. The P.

Scale dependence of coral reef oases and their environmental correlates.

Identifying relatively intact areas within ecosystems and determining the conditions favoring their existence is necessary for effective management in the context of widespread environmental degradation. In this study, we used 3766 surveys of randomly selected sites in the United States and U.S.

Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes.

Dredging poses a potential threat to coral reefs, yet quantifying impacts is often difficult due to the large spatial footprint of potential effects and co-occurrence of other disturbances. Here we analyzed in situ monitoring data and remotely-sensed sediment plumes to assess impacts of the 2013-2015 Port of Miami dredging on corals and reef habitat. To control for contemporaneous bleaching and disease, we analyzed the spatial distribution of impacts in relation to the dredged channel.

The great Atlantic belt.

Pelagic is abundant in the Sargasso Sea, but a recurrent great Atlantic belt (GASB) has been observed in satellite imagery since 2011, often extending from West Africa to the Gulf of Mexico. In June 2018, the 8850-kilometer GASB contained >20 million metric tons of biomass. The spatial distribution of the GASB is mostly driven by ocean circulation.

VIIRS captures phytoplankton vertical migration in the NE Gulf of Mexico.

In summer 2014, a toxic Karenia brevis bloom (red tide) occurred in the NE Gulf of Mexico, during which vertical migration of K. brevis has been observed from glider measurements. The current study shows that satellite observations from the Visible Infrared Imaging Radiometer Suite (VIIRS) can capture changes in surface reflectance and chlorophyll concentration occurring within 2h, which may be attributed this K.

Vertical migration of Karenia brevis in the northeastern Gulf of Mexico observed from glider measurements.

The toxic marine dinoflagellate, Karenia brevis (the species responsible for most of red tides or harmful algal blooms in the Gulf of Mexico), is known to be able to swim vertically to adapt to the light and nutrient environments, nearly all such observations have been made through controlled experiments using cultures. Here, using continuous 3-dimensional measurements by an ocean glider across a K. brevis bloom in the northeastern Gulf of Mexico between 1 and 8 August 2014, we show the vertical migration behavior of K.

Island building in the South China Sea: detection of turbidity plumes and artificial islands using Landsat and MODIS data.

The South China Sea is currently in a state of intense geopolitical conflict, with six countries claiming sovereignty over some or all of the area. Recently, several countries have carried out island building projects in the Spratly Islands, converting portions of coral reefs into artificial islands. Aerial photography and high resolution satellites can capture snapshots of this construction, but such data are lacking in temporal resolution and spatial scope.

A harmful algal bloom of Karenia brevis in the northeastern Gulf of Mexico as revealed by MODIS and VIIRS: a comparison.

The most recent Visible Infrared Imager Radiometer Suite (VIIRS) is not equipped with a spectral band to detect solar-stimulated phytoplankton fluorescence. The lack of such a band may affect the ability of VIIRS to detect and quantify harmful algal blooms (HABs) in coastal waters rich in colored dissolved organic matter (CDOM) because of the overlap of CDOM and chlorophyll absorption within the blue-green spectrum. A recent HAB dominated by the toxin-producing dinoflagellate Karenia brevis in the northeastern Gulf of Mexico, offshore of Florida's Big Bend region, allowed for comparison of the capacities of VIIRS and Moderate Resolution Imaging Spectroradiometer (MODIS) to detect blooms in CDOM-rich waters.

What experimental factors influence the accuracy of retention projections in gas chromatography-mass spectrometry?

Programmed-temperature gas chromatographic (GC) retention information is difficult to share because it depends on so many experimental factors that vary among laboratories. Though linear retention indexing cannot properly account for experimental differences, retention times can be accurately calculated, or "projected", from shared isothermal retention vs. temperature (T) relationships, but only if the temperature program and hold-up time vs.

"Measure Your Gradient": a new way to measure gradients in high performance liquid chromatography by mass spectrometric or absorbance detection.

The gradient produced by an HPLC is never the same as the one it is programmed to produce, but non-idealities in the gradient can be taken into account if they are measured. Such measurements are routine, yet only one general approach has been described to make them: both HPLC solvents are replaced with water, solvent B is spiked with 0.1% acetone, and the gradient is measured by UV absorbance.

Impact of reversed phase column pairs in comprehensive two-dimensional liquid chromatography.

A major issue in optimizing the resolving power of two-dimensional chromatographic separations is the choice of the two phases so as to maximize the distribution of the analytes over the separation space. In this work, we studied the choice of appropriate reversed phases to use in on-line comprehensive two-dimensional liquid chromatography (LC×LC). A set of four chemically different conventional bonded reversed phases was used in the first dimension.

"Retention projection" enables reliable use of shared gas chromatographic retention data across laboratories, instruments, and methods.

Gas chromatography/mass spectrometry (GC/MS) is a primary tool used to identify compounds in complex samples. Both mass spectra and GC retention times are matched to those of standards; however, it is often impractical to have standards on hand for every compound of interest, so we must rely on shared databases of MS data and GC retention information. Unfortunately, retention databases (e.

Determination of steroids, caffeine and methylparaben in water using solid phase microextraction-comprehensive two dimensional gas chromatography-time of flight mass spectrometry.

Analysis of several emerging contaminants (steroids, caffeine and methylparaben) in water using automated solid-phase microextraction with comprehensive two dimensional gas chromatography coupled to time of flight mass spectrometry (SPME-GCxGC-ToF/MS) is presented. Experimental design was used to determine the best SPME extraction conditions and the steroids were not derivatized prior to injection. SPME-GCxGC-ToF/MS provided linear ranges from 0.

Analysis of Salvinorin A in plants, water, and urine using solid-phase microextraction-comprehensive two-dimensional gas chromatography-time of flight mass spectrometry.

Salvinorin A, a psychoactive hallucinogen, and related compounds, were analyzed in plants, water, and urine using liquid-liquid extraction (LLE), solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC×GC-ToFMS). A semi-qualitative study of the extraction of Salvinorin A and analogs from Salvia divinorum plants by LLE showed ppb levels of Salvinorin A and several analogs in the leaves and stems of S. divinorum plants, much lower than expected.