Diel changes in nitrite concentration in the chlorophyll maximum in the Gulf of Mexico

French, Deborah P.; Furnas, Miles; Smayda, Theodore J.

doi:10.1016/0198-0149(83)90018-3

Cited by 34 publications

(15 citation statements)

References 25 publications

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“…There also remain questions on variability in the depth (and therefore the light and nutrient concentrations that the resident phytoplankton are exposed to) of the PNM. At least two studies show that on the timescale of hours, the PNM can shoal or deepen by tens of meters (French et al 1983;Dore and Karl 1996b). There is also the possibility of a disconnect between the species used in culture experiments examining NO 2 2 release (primarily diatoms and flagellates) and the cyanobacteria and picoeukaryotes that are dominant at the PNM in the ocean.…”

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

“…This poor coordination between intracellular NO 2 3 and NO 2 2 reduction pathways is also seen in the dinoflagellates Scrippsiella trochoidea, Alexandrium minutum, and Heterosigma cartarae (Flynn and Flynn 1998;, but not in the diatom Thalassiosira weissflogii . It is reasonable to hypothesize that NO 2 2 shallower than the nitracline could arise from ''sloppy'' phytoplankton in the DCM exposed to periodic low-level NO 2 3 injections or very short-lived light/dark transitions at sunrise (e.g., Anderson and Roels 1981) or sunset (French et al 1983) when the 1% PAR depth is rapidly deepening or shoaling. The physiological mechanism for this could be the transient, light-induced uncoupling of NO 2 3 and NO 2 2 reduction (Lomas et al 2000) whereby NO 2 3 is reduced and NO 2 2 released to the media to dissipate excess absorbed light energy.…”

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

“…This conclusion for natural populations is supported by field observations showing that surface NO 2 2 and NO 2 3 concentrations remain low and constant during the stratified summer in the subtropical gyres, suggesting that nitrification does occur in the surface ocean during daylight at low but measurable rates (Ward 1987;Raimbault et al 1999;Lipschultz 2001; ,5 nmol L 21 d 21 ). PNM NO 2 2 concentrations in the Gulf of Mexico (French et al 1983) have been shown to increase during the day because of phytoplankton release, yet in the North Pacific (Dore and Karl 1996a) NO 2 2 concentrations increase at night because of nitrification, suggesting a temporal component (perhaps day/night oscillations in irradiance) as well as a taxonomic component (i.e., phytoplankton vs. bacteria) to understanding the PNM in the ocean. Moreover, there is no a priori reason to believe that all phytoplankton or all nitrifying bacteria display the same physiological characteristics, further complicating our interpretation of the present and future data.…”

Section: Winter Mixingmentioning

confidence: 99%

“…Both of these studies (Kiefer et al 1976;French et al 1983) rely on a model of light limitation of net phytoplankton NO 2 2 reduction to explain the production of the PNM. It is inconsistent with the data of Olson (1980) release?…”

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

“…Seven years later, French et al (1983) were motivated to revisit the role of phytoplankton excretion in the PNM after observing strong diel variability of NO 2 2 in the PNM of the Gulf of Mexico. By using a quasi-Lagrangian approach, lateral advection could be eliminated to a first approximation as a source of the increasing daytime NO 2 2 concentrations, and physical dispersion could therefore be restricted to the vertical domain.…”

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

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Forming the primary nitrite maximum: Nitrifiers or phytoplankton?

Lomas¹,

Lipschultz²

2006

Limnol. Oceanogr.

224

176

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As intermediary in a number of key biological processes, the dynamics of oceanic NO 2 2 concentrations have historically been used as an indicator of the balance between oxidative and reductive pathways in the marine nitrogen cycle. As appreciation of the role of NO 2 2 in the marine nitrogen cycle grew through the 1960s and 1970s, and data sets from different ocean basins became available, a common feature was observed in stratified water columns: a peak in NO 2 2 concentrations at the base of the euphotic zone, with near zero concentrations both shallower and deeper. These concentrations are significant; they commonly range between 10 and 400 nmol L 21 but as high as 4,500 nmol L 21 . This peak in NO 2 2 concentration is termed the primary nitrite maximum (PNM). Since the 1960s, the mechanisms sustaining the ubiquitous PNM have remained uncertain, with available data supporting either bacterial nitrification or NO 2 2 release by phytoplankton. Simple box models have reproduced the PNM feature with nitrification as the source of NO 2 2 , whereas others have succeeded solely with phytoplankton. Conclusive identification of the mechanism(s) maintaining the PNM in the world's oceans has yet to be achieved, but the preponderance of data supports phytoplankton excretion, with nitrification likely playing only a supporting role. Furthermore, there are a number of potentially important inconsistencies in the role of nitrification between culture studies and field observations. Biological-physical interactions are likely also important in controlling PNM formation and maintenance.

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Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

Section: Winter Mixingmentioning

confidence: 99%

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

Section: Proposed Models Of Pnm Formation and Maintenancementioning

confidence: 99%

See 3 more Smart Citations

Forming the primary nitrite maximum: Nitrifiers or phytoplankton?

Lomas¹,

Lipschultz²

2006

Limnol. Oceanogr.

224

176

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Nitrification in Aquatic Systems

Ward

2003

Encyclopedia of Environmental Microbiology

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Physiology and Energetics of Nitrifying Bacteria Phylogeny of Bacteria Involved in Nitrification Role of Nitrification in the Nitrogen Cycle Distribution and Abundance of Nitrifiers in Aquatic Habitats Methods for Measuring Nitrification in Water and Sediments Distribution of Nitrification in Water and Sediments Environmental Variables that Affect Nitrification Rates and Distributions Nitrous Oxide and Nitric Oxide Production During Nitrification Nitrification and Methane Oxidation

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Biogeochemical and metagenomic analysis of nitrite accumulation in the Gulf of Mexico hypoxic zone

Bristow

Sarode

Cartee

et al. 2015

Limnology & Oceanography

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The Louisiana Shelf in the Gulf of Mexico experiences recurrent bottom water hypoxia under summertime eutrophic conditions. The onset, maintenance, and breakdown of hypoxia are associated with dynamic microbial biogeochemical cycles. However, the distribution of microbial taxa and metabolisms across Shelf oxygen gradients remains under-characterized. We combined biogeochemical analyses of nitrogen (N) distributions and metabolic rates with metagenomic and metatranscriptomic analysis of summertime Shelf waters. Samples from an east-west transect during July 2012 revealed an inverse relationship between nitrite and oxygen concentrations, with concentrations exceeding 1 lmol L 21 at 50% oxygen saturation and reaching 4.6 lmol L 21 at the most oxygen-depleted sites. Historical data confirms that nitrite accumulation occurs frequently in this region both above and below the hypoxic threshold. Experimental incubations demonstrated a strong decoupling between the two steps of nitrification, with ammonia oxidation proceeding up to 30 times faster than nitrite oxidation under low oxygen. 16S rRNA gene, metagenome, and metatranscriptome sequencing revealed a diverse microbial community, stratified over shallow (< 10 m) depth gradients, with an enrichment of ammonia-oxidizing Thaumarchaeota genes and transcripts in deeper more oxygendepleted layers, and a comparatively low representation of sequences related to nitrite oxidation. A range of factors, including temperature and substrate availability, which may be linked indirectly to bottom water oxygen content, potentially drives decoupling of ammonia and nitrite oxidation on the Louisiana Shelf. Nitrite accumulation in hypoxic zones remains understudied and may have important effects on microbial nitrogen flux, algal dynamics, and production.

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Diel changes in nitrite concentration in the chlorophyll maximum in the Gulf of Mexico

Cited by 34 publications

References 25 publications

Forming the primary nitrite maximum: Nitrifiers or phytoplankton?

Forming the primary nitrite maximum: Nitrifiers or phytoplankton?

Nitrification in Aquatic Systems

Biogeochemical and metagenomic analysis of nitrite accumulation in the Gulf of Mexico hypoxic zone

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