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Nitrous Oxide Distributions in the Oxygenated Water Column of the Sargasso Sea

Abstract. 

"This study presents dissolved nitrous oxide (N2O) concentrations in the water column at the Bermuda Atlantic Time-series Study (BATS) station and uses a subset of these measurements to estimate air-to-sea flux for four specific time points between September 2018 and June 2019. N2O concentrations at BATS were in the range of 4.0 nmol L−1–16.9 nmol L−1, with vertical profiles which were the mirror inverse of dissolved oxygen. Regardless of season, N2O concentration maxima were found within the oxygen minimum zone (OMZ). The highest maximum N2O values were observed in November and lowest in October. [...]".

 

Source: Taylor & Francis Online
Authors: Annaliese C.S. Meyer et al. 
DOI: https://doi.org/10.1080/07055900.2022.2153325

Read the full article here.


Diversity and relative abundance of ammonia- and nitrite-oxidizing microorganisms in the offshore Namibian hypoxic zone

Abstract.

"Nitrification, the microbial oxidation of ammonia (NH3) to nitrite (NO2) and NO2 to nitrate (NO3), plays a vital role in ocean nitrogen cycling. Characterizing the distribution of nitrifying organisms over environmental gradients can help predict how nitrogen availability may change with shifting ocean conditions, for example, due to loss of dissolved oxygen (O2). [...]"

Source: PLoS ONE
Authors: Evan Lau et al.
DOI: 10.1371/journal.pone.0217136

Read the full article here.


Hydroxylamine as a Potential Indicator of Nitrification in the Open Ocean

Abstract.

"Hydroxylamine (NH2OH), a short‐lived intermediate in the nitrogen cycle, is a potential precursor of nitrous oxide (N2O) in the ocean. However, measurements of NH2OH in the ocean are sparse. Here we present a data set of depth profiles of NH2OH from the equatorial Atlantic Ocean and the eastern tropical South Pacific and compare it to N2O, nitrate, and nitrite profiles under varying oxygen conditions. [...]"

Source: Geophysical Research Letters
Authors: Frederike Korth et al.
DOI: 10.1029/2018GL080466

Read the full article here.


Hydroxylamine as a Potential Indicator of Nitrification in the Open Ocean

Abstract.

"Hydroxylamine (NH2OH), a short‐lived intermediate in the nitrogen cycle, is a potential precursor of nitrous oxide (N2O) in the ocean. However, measurements of NH2OH in the ocean are sparse. Here we present a data set of depth profiles of NH2OH from the equatorial Atlantic Ocean and the eastern tropical South Pacific and compare it to N2O, nitrate, and nitrite profiles under varying oxygen conditions. The presence of NH2OH in surface waters points toward surface nitrification in the upper 100 m. [...]"

Source: Geophysical Research Letters
Authors: Frederike Korth et al.
DOI: 10.1029/2018GL080466

Read the full article here.


The impact of primary and export production on the formation of the secondary nitrite maximum: A model study

Abstract.

"The so-called secondary nitrite maximum (SNM) is a pronounced subsurface feature in many oxygen deficient zones of the ocean. A nitrite layer of up to several hundred meters thickness indicates high microbial activity and nitrogen loss from the system. To study the effects of primary and export production on the SNM, we have developed a one-dimensional ecosystem model for oxygen deficient zones. Our model couples the marine nitrogen and oxygen cycles with physical water column processes, includes euphotic, aphotic, aerobic and anaerobic processes and thereby dynamically describes source and sink processes for nitrite. [...]"

Source: Ecological Modelling
Authors: Aike Beckmann and Inga Hense
DOI: 10.1016/j.ecolmodel.2017.05.014

Read the full article here.


Rising water temperatures endanger health of coastal ecosystems, study finds

"Increasing water temperatures are responsible for the accumulation of a chemical called nitrite in marine environments throughout the world, a symptom of broader changes in normal ocean biochemical pathways that could ultimately disrupt ocean food webs, according to new research from the University of Georgia. " 

Source: phys.org

Full article


Temperature Decouples Ammonium and Nitrite Oxidation in Coastal Waters

Abstract.

"Nitrification is a two-step process linking the reduced and oxidized sides of the nitrogen cycle. These steps are typically tightly coupled with the primary intermediate, nitrite, rarely accumulating in coastal environments. Nitrite concentrations can exceed 10 μM during summer in estuarine waters adjacent to Sapelo Island, Georgia, U.S.A. Similar peaks at other locations have been attributed to decoupling of the two steps of nitrification by hypoxia; however, the waters around Sapelo Island are aerobic and well-mixed.  Experiments examining the response to temperature shifts of a nitrifying assemblage composed of the same organisms found in the field indicate that ammonia- and nitrite-oxidation become uncoupled between 20 and 30 °C, leading to nitrite accumulation. [...]"

Source: Environmental Science & Technology 
Authors: Sylvia C. Schaefer, James T. Hollibaugh
DOI: 10.1021/acs.est.6b03483

Full article

 


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