Quantifying the Relative Importance of Riverine and Open‐Ocean Nitrogen Sources for Hypoxia Formation in the Northern Gulf of Mexico
"The Mississippi and Atchafalaya River System discharges large amounts of freshwater and nutrients into the northern Gulf of Mexico (NGoM). These lead to increased stratification and elevate primary production in the outflow region. Consequently, hypoxia (oxygen <62.5 mmol/m3), extending over an area of roughly 15,000 km2, forms every summer in bottom waters. [...]"
Source: JGR Oceans
Authors: Fabian Große et al.
Nitrifier abundance and diversity peak at deep redox transition zones
"More than half of the global ocean floor is draped by nutrient-starved sediments characterized by deep oxygen penetration and a prevalence of oxidized nitrogen. Despite low energy availability, this habitat hosts a vast microbial population, and geochemical characteristics suggest that nitrogen compounds are an energy source critical to sustaining this biomass. [...]"
Source: Scientific Reports
Authors: Rui Zhao et al.
Ammonium availability in the Late Archaean nitrogen cycle
"The bioavailability of essential nutrients such as nitrogen and phosphorus has fluctuated with the chemical evolution of Earth surface environments over geological timescales. However, significant uncertainty remains over the evolution of Earth’s early nitrogen cycle, particularly how and when it responded to the evolution of oxygenic photosynthesis. [...]"
Source: Nature Geoscience
Authors: J. Yang et al.
Remote and local drivers of oxygen and nitrate variability in the shallow oxygen minimum zone off Mauritania in June 2014
"Upwelling systems play a key role in the global carbon and nitrogen cycles and are also of local relevance due to their high productivity and fish resources. To capture and understand the high spatial and temporal variability in physical and biogeochemical parameters found in these regions, novel measurement techniques have to be combined in an interdisciplinary manner. Here we use high-resolution glider-based physical–biogeochemical observations in combination with ship-based underwater vision profiler, sensor and bottle data to investigate the drivers of oxygen and nitrate variability across the shelf break off Mauritania in June 2014. [...]"
Authors: Soeren Thomsen et al.