Atmospheric nitrogen inputs to the Delaware Inland Bays: the role of ammonia

2005 ◽  
Vol 135 (3) ◽  
pp. 433-443 ◽  
Author(s):  
Joseph R. Scudlark ◽  
Jennifer A. Jennings ◽  
Megan J. Roadman ◽  
Karen B. Savidge ◽  
William J. Ullman
Keyword(s):  
Atmospheric Nitrogen ◽  
Inland Bays ◽  
Nitrogen Inputs ◽  
Delaware Inland Bays

scholarly journals The role of air-sea exchange in the marine nitrogen cycle

2006 ◽  
Vol 3 (3) ◽  
pp. 271-280 ◽  
Author(s):  
T. Jickells
Keyword(s):  
Nitrogen Cycle ◽  
Coastal Waters ◽  
Algal Blooms ◽  
Long Range Transport ◽  
Atmospheric Nitrogen ◽  
Ocean Productivity ◽  
Nitrogen Inputs ◽  
Range Transport ◽  
Atmospheric Inputs

Abstract. This contribution to the Spot-On volume considers the magnitude and composition of atmospheric nitrogen inputs to the oceans and then goes on to consider the impacts of these inputs. Effects in open ocean and coastal areas are probably different. Offshore atmospheric inputs may produce a small enhancement of overall ocean productivity and hence CO2 drawdown. In coastal waters atmospheric inputs contribute significantly to overall eutrophication pressure, but evidence that they trigger algal blooms is limited. Management of atmospheric inputs to coastal waters to mitigate eutrophication pressures requires that emissions be managed over a wide area reflecting the efficient long range transport of atmospheric nitrogen. Strategies for management of oxidised and reduced nitrogen deposition will be different reflecting their different rates of deposition.

scholarly journals The role of air-sea exchange in the marine nitrogen cycle

2006 ◽  
Vol 3 (1) ◽  
pp. 183-210 ◽  
Author(s):  
T. Jickells
Keyword(s):  
Nitrogen Cycle ◽  
Coastal Waters ◽  
Algal Blooms ◽  
Long Range Transport ◽  
Atmospheric Nitrogen ◽  
Ocean Productivity ◽  
Nitrogen Inputs ◽  
Range Transport ◽  
Atmospheric Inputs

Abstract. This contribution to the Spot-On volume considers the magnitude and composition of atmospheric nitrogen inputs to the oceans and then goes on to consider the impacts of these inputs. Effects in open ocean and coastal areas are probably different. Offshore atmospheric inputs may produce a small enhancement of overall ocean productivity and hence CO2 drawdown. In coastal waters atmospheric inputs contribute significantly to overall eutrophication pressure, but evidence that they trigger algal blooms is limited. Management of atmospheric inputs to coastal waters to mitigate eutrophication pressures requires that emissions be managed over a wide area reflecting the efficient long range transport of atmospheric nitrogen. Strategies for management of oxidised and reduced nitrogen deposition will be different reflecting their different rates of deposition.

Nitrate reductases and hemoglobins control nitrogen-fixing symbiosis by regulating nitric oxide accumulation

2020 ◽  
Author(s):  
Antoine Berger ◽  
Alexandre Boscari ◽  
Alain Puppo ◽  
Renaud Brouquisse
Keyword(s):  
Nitric Oxide ◽  
Defense Responses ◽  
Nodule Formation ◽  
No Production ◽  
Degradation Pathways ◽  
Atmospheric Nitrogen ◽  
Metabolic Intermediate ◽  
Hypoxic Environment ◽  
Nitrate Reductases

Abstract The interaction between legumes and rhizobia leads to the establishment of a symbiotic relationship between plant and bacteria. This is characterized by the formation of a new organ, the nodule, which facilitates the fixation of atmospheric nitrogen (N2) by nitrogenase through the creation of a hypoxic environment. Nitric oxide (NO) accumulates at each stage of the symbiotic process. NO is involved in defense responses, nodule organogenesis and development, nitrogen fixation metabolism, and senescence induction. During symbiosis, either successively or simultaneously, NO regulates gene expression, modulates enzyme activities, and acts as a metabolic intermediate in energy regeneration processes via phytoglobin-NO respiration and the bacterial denitrification pathway. Due to the transition from normoxia to hypoxia during nodule formation, and the progressive presence of the bacterial partner in the growing nodules, NO production and degradation pathways change during the symbiotic process. This review analyzes the different source and degradation pathways of NO, and highlights the role of nitrate reductases and hemoproteins of both the plant and bacterial partners in the control of NO accumulation.

scholarly journals Monitoring Heavy Metals near Wastewater Facility in Delaware Inland Bays Tidal Canal

2017 ◽  
Vol 09 (08) ◽  
pp. 985-998
Author(s):  
Amy C. Cannon ◽  
Lathadevi K. Chintapenta ◽  
Gulnihal Ozbay
Keyword(s):  
Heavy Metals ◽  
Inland Bays ◽  
Delaware Inland Bays

Atmospheric nitrogen inputs into the coastal ecosystem (ANICE): Description

2000 ◽  
Vol 31 ◽  
pp. 729-730
Author(s):  
G. de Leeuw ◽  
L.H. Cohen ◽  
G.J. Kunz ◽  
M.M. Moerman ◽  
G. Geernaert ◽  
...  
Keyword(s):  
Coastal Ecosystem ◽  
Atmospheric Nitrogen ◽  
Nitrogen Inputs

scholarly journals Interactions of PatA with the Divisome during Heterocyst Differentiation in Anabaena

mSphere ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Ana Valladares ◽  
Cristina Velázquez-Suárez ◽  
Antonia Herrero
Keyword(s):  
Cell Division ◽  
Organic Nitrogen ◽  
Atmospheric Nitrogen ◽  
Differentiation Process ◽  
Vegetative Cells ◽  
Genetic Changes ◽  
Heterocyst Differentiation ◽  
Essential Components ◽  
Z Ring

ABSTRACT The Anabaena organismic unit is a filament of communicating cells. Under conditions of nitrogen scarcity, some cells along the filament differentiate into heterocysts, which are specialized in the fixation of atmospheric N2 and provide the vegetative cells with N2 fixation products. At a certain stage, the differentiation process becomes irreversible, so that even when nitrogen is replenished, no return to the vegetative cell state takes place, possibly as a consequence of loss of cell division capacity. Upon N-stepdown, midcell FtsZ-rings were detected in vegetative cells, but not in differentiating cells, and this was also the case for ZipN, an essential protein that participates in FtsZ tethering to the cytoplasmic membrane and divisome organization. Later, expression of ftsZ was arrested in mature heterocysts. PatA is a protein required for the differentiation of intercalary heterocysts in Anabaena. The expression level of the patA gene was increased in differentiating cells, and a mutant strain lacking PatA exhibited enhanced FtsZ-rings. PatA was capable of direct interactions with ZipN and SepF, another essential component of the Anabaena Z-ring. Thus, PatA appears to promote inhibition of cell division in the differentiating cells, allowing progress of the differentiation process. PatA, which in mature heterocysts was detected at the cell poles, could interact also with SepJ, a protein involved in production of the septal junctions that provide cell-cell adhesion and intercellular communication in the filament, hinting at a further role of PatA in the formation or stability of the intercellular structures that are at the basis of the multicellular character of Anabaena. IMPORTANCE Anabaena is a cyanobacterial model that represents an ancient and simple form of biological multicellularity. The Anabaena organism is a filament of cohesive and communicating cells that can include cells specialized in different tasks. Thus, under conditions of nitrogen scarcity, certain cells of the filament differentiate into heterocysts, which fix atmospheric nitrogen and provide organic nitrogen to the rest of cells, which, in turn, provide heterocysts with organic carbon. Heterocyst differentiation involves extensive morphological, biochemical, and genetic changes, becoming irreversible at a certain stage. We studied the regulation during heterocyst differentiation of several essential components of the Anabaena cell division machinery and found that protein PatA, which is required for differentiation and is induced in differentiating cells, interacts with essential cell division factors and destabilizes the cell division complex. This suggests a mechanism for establishment of commitment to differentiation by inhibition of cell division.

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