Mark A. Altabet
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View article: Meso‐ and Submesoscale Circulation Origins for Subsurface Oxygen Intrusions Into the Oxygen Deficient Zone of the Eastern Tropical North Pacific
Meso‐ and Submesoscale Circulation Origins for Subsurface Oxygen Intrusions Into the Oxygen Deficient Zone of the Eastern Tropical North Pacific Open
Subsurface oxygen maxima (SOM) are recurrent but poorly understood features within the eastern tropical North Pacific oxygen deficient zone (ODZ). Here, we analyze a subsurface oxygen maximum (SOM) observed during the SR2114 cruise using i…
View article: Compound-Specific and Intramolecular δ<sup>15</sup>N Analysis of a Poly-Nitrogenous Amino Acid: Histidine
Compound-Specific and Intramolecular δ<sup>15</sup>N Analysis of a Poly-Nitrogenous Amino Acid: Histidine Open
Histidine (HIS) is an essential amino acid (AA) with key physiological roles in metal chelation and proton buffering. Its three nitrogen (N) atoms─one α-amino and two in the imidazole side chain─are incorporated through distinct biosynthet…
View article: Compound-Specific and Intramolecular δ15N analysis of a Poly-Nitrogenous Amino Acid: Histidine
Compound-Specific and Intramolecular δ15N analysis of a Poly-Nitrogenous Amino Acid: Histidine Open
Histidine (HIS) is an essential amino acid (AA) with key physiological roles in metal chelation and proton buffering. Its three nitrogen (N) atoms—one α-amino and two in the imidazole side chain—are incorporated through distinct biosynthet…
View article: Anoxic waters constrain the vertical distribution of fish developmental stages in an oxygen minimum zone
Anoxic waters constrain the vertical distribution of fish developmental stages in an oxygen minimum zone Open
In the Eastern Tropical North Pacific Oxygen Minimum Zone (ETNP‐OMZ), fish larvae undergo development amidst highly variable dissolved oxygen environments. As OMZs expand, understanding the implications of low‐oxygen environments on fish d…
View article: Editorial: Recent developments in oxygen minimum zones biogeochemistry
Editorial: Recent developments in oxygen minimum zones biogeochemistry Open
EDITORIAL article Front. Mar. Sci., 05 December 2023Sec. Marine Biogeochemistry Volume 10 - 2023 | https://doi.org/10.3389/fmars.2023.1333731
View article: Autonomous observations of biogenic N2 in the Eastern Tropical North Pacific using profiling floats equipped with gas tension devices
Autonomous observations of biogenic N2 in the Eastern Tropical North Pacific using profiling floats equipped with gas tension devices Open
Oxygen Deficient Zones (ODZs) of the world’s oceans represent a relatively small fraction of the ocean by volume (<0.05% for suboxic and<5% for hypoxic) yet are receiving increased attention by experimentalists and modelers due to th…
View article: Marine N2O cycling from high spatial resolution concentration, stable isotopic and isotopomer measurements along a meridional transect in the eastern Pacific Ocean
Marine N2O cycling from high spatial resolution concentration, stable isotopic and isotopomer measurements along a meridional transect in the eastern Pacific Ocean Open
Nitrous oxide (N 2 O) is a potent greenhouse gas and ozone depleting substance, with the ocean accounting for about one third of global emissions. In marine environments, a significant amount of N 2 O is produced by biological processes in…
View article: Controls on surface distributions of dissolved organic carbon and nitrogen in the southeast Pacific Ocean
Controls on surface distributions of dissolved organic carbon and nitrogen in the southeast Pacific Ocean Open
Here we use data from three meridional survey cruises that took place in 1994, 2007/2008 and 2016/2017 in the southeast Pacific Ocean to investigate controls on surface distributions of dissolved organic carbon and nitrogen (DOC and DON, r…
View article: Stable Isotope Ecology of Invasive Lionfish (Pterois volitans and P. miles) in Bermuda
Stable Isotope Ecology of Invasive Lionfish (Pterois volitans and P. miles) in Bermuda Open
Over the past three decades, lionfish (Pterois volitans and Pterois miles) from the Indo-Pacific have invaded the northwest Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico. As generalist predators with a broad diet, they could pose a…
View article: Kelp Beds and Their Local Effects on Seawater Chemistry, Productivity, and Microbial Communities
Kelp Beds and Their Local Effects on Seawater Chemistry, Productivity, and Microbial Communities Open
Our research showed that kelp beds locally increased the pH, oxygen, and aragonite saturation state of the seawater, while seawater inorganic carbon content and total alkalinity were lowered. Kelp beds depleted nitrate and phosphorus conce…
View article: Investigating the effect of El Niño on nitrous oxide distribution in the eastern tropical South Pacific
Investigating the effect of El Niño on nitrous oxide distribution in the eastern tropical South Pacific Open
The open ocean is a major source of nitrous oxide (N2O), an atmospheric trace gas attributable to global warming and ozone depletion. Intense sea-to-air N2O fluxes occur in major oceanic upwelling regions such as the eastern tropical South…
View article: Remote Western Arctic Nutrients Fuel Remineralization in Deep Baffin Bay
Remote Western Arctic Nutrients Fuel Remineralization in Deep Baffin Bay Open
The oceanic nitrogen cycle is critically important for the partitioning of greenhouse gases between ocean and atmosphere. Baffin Bay connects ocean regions that are major sources (North Atlantic) and sinks (North Pacific and western Arctic…
View article: Enhanced microbial nitrogen transformations in association with macrobiota from the rocky intertidal
Enhanced microbial nitrogen transformations in association with macrobiota from the rocky intertidal Open
Microbial nitrogen processing in direct association with marine animals and seaweeds is poorly understood. Microbes can both attach to the surfaces of macrobiota and make use of their excreted nitrogen and dissolved organic carbon (DOC). W…
View article: Interpreting Mosaics of Ocean Biogeochemistry
Interpreting Mosaics of Ocean Biogeochemistry Open
Advances in technology and modeling capabilities are driving a surge in progress in our understanding of how ocean ecosystems mix and mingle on medium to small scales.
View article: Investigating the effect of El Niño on nitrous oxide distribution in the Eastern Tropical South Pacific
Investigating the effect of El Niño on nitrous oxide distribution in the Eastern Tropical South Pacific Open
The open ocean is a major source of atmospheric warming and ozone depleting gas nitrous oxide (N2O). Intense sea-to-air fluxes of N2O occur in major oceanic upwelling regions such as the Eastern Tropical South Pacific Ocean (ETSP). The ETS…
View article: Ventilation of Northern and Southern Sources of Aged Carbon in the Eastern Equatorial Pacific During the Younger Dryas Rise in Atmospheric CO<sub>2</sub>
Ventilation of Northern and Southern Sources of Aged Carbon in the Eastern Equatorial Pacific During the Younger Dryas Rise in Atmospheric CO<sub>2</sub> Open
Atmospheric carbon dioxide (CO 2 ) levels rose by ~90 ppmv during the last deglaciation, but the source of this carbon remains unknown. One popular hypothesis suggests carbon accumulated in the deep Southern Ocean, becoming increasingly ra…
View article: Copepod-Associated Gammaproteobacteria Respire Nitrate in the Open Ocean Surface Layers
Copepod-Associated Gammaproteobacteria Respire Nitrate in the Open Ocean Surface Layers Open
Microbial dissimilatory nitrate reduction to nitrite, or nitrate respiration, was detected in association with copepods in the oxygenated water column of the North Atlantic subtropical waters. These unexpected rates correspond to up to 0.0…
View article: Single cell genomic and transcriptomic evidence for the use of alternative nitrogen substrates by anammox bacteria
Single cell genomic and transcriptomic evidence for the use of alternative nitrogen substrates by anammox bacteria Open
Anaerobic ammonium oxidation (anammox) contributes substantially to ocean nitrogen loss, particularly in anoxic marine zones (AMZs). Ammonium is scarce in AMZs, raising the hypothesis that organic nitrogen compounds may be ammonium sources…
View article: Enhanced microbial nitrogen transformations in association with intertidal macrobiota
Enhanced microbial nitrogen transformations in association with intertidal macrobiota Open
Microbial nitrogen processing in direct association with marine animals and seaweeds is poorly understood. Macrobiota supply a substrate for microbes to reside, and a source of excreted nitrogen and dissolved organic carbon (DOC). We teste…
View article: N<sub>2</sub>O production and consumption from stable isotopic and concentration data in the Peruvian coastal upwelling system
N<sub>2</sub>O production and consumption from stable isotopic and concentration data in the Peruvian coastal upwelling system Open
The ocean is an important source of nitrous oxide (N 2 O) to the atmosphere, yet the factors controlling N 2 O production and consumption in oceanic environments are still not understood nor constrained. We measured N 2 O concentrations an…
View article: Silicon and nitrogen cycling in the upwelling area off Peru: A dual isotope approach
Silicon and nitrogen cycling in the upwelling area off Peru: A dual isotope approach Open
We present a comparison of the dissolved stable isotope composition of silicate (δ30Si(OH)4) and nitrate (δ15 inline image) to investigate the biogeochemical processes controlling nutrient cycling in the upwelling area off Peru, where one …