scholarly journals A 15N tracer method for the measurement of dissolved organic nitrogen release by phytoplankton

1991 ◽  
Vol 77 ◽  
pp. 171-182 ◽  
Author(s):  
DA Bronk ◽  
PM Glibert
Keyword(s):  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
15N Tracer ◽  
Nitrogen Release ◽  
Tracer Method

scholarly journals Significance of N<sub>2</sub> fixation in dissolved fractions of organic nitrogen

2010 ◽  
Vol 7 (1) ◽  
pp. 765-786 ◽  
Author(s):  
U. Konno ◽  
U. Tsunogai ◽  
D. D. Komatsu ◽  
S. Daita ◽  
F. Nakagawa ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
High Sensitivity ◽  
Nitrogen Budget ◽  
Tracer Method ◽  
Fixed Nitrogen

Abstract. Using the 15N2 tracer method and high-sensitivity δ15N analytical systems, we determined N2 fixation rates by dividing fractions into particulate organic nitrogen (PON: >0.7 μm) and dissolved organic nitrogen (DON: <0.7 μm). While N2 fixation in the DON fraction had been ignored in previous studies, we found significant N2 fixation signal in the DON fraction in our study. The areal N2 fixation rates estimated from the PON fractions varied from <1–160 μmol N m−2 d−1, and those estimated from the DON fractions ranged from <0.5–54 μmol N m−2 d−1. Thus, N2 fixation in the DON fractions accounted for 50% (ranging from <10% to 84%) of the total N2 fixation rates on an average. The new total N2 fixation flux, which includes fixation in DON fractions, has possibility to double the original estimates; therefore, the revised influx may reduce the imbalance in the global oceanic fixed nitrogen budget.

scholarly journals Nitrogen Release in Pristine and Drained Peat Profiles in Response to Water Table Fluctuations: A Mesocosm Experiment

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Merjo P. P. Laine ◽  
Rauni Strömmer ◽  
Lauri Arvola
Keyword(s):  
Water Table ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Mesocosm Experiment ◽  
Nitrogen Release ◽  
Hydrological Conditions ◽  
Water Table Fluctuations ◽  
Drying And Rewetting ◽  
Response To Water ◽  
Artificial Water

In the northern hemisphere, variability in hydrological conditions was suggested to increase as a consequence of climate warming, which may result in longer droughts than the area has experienced before. Due to their predominately anoxic conditions, peatlands are expected to respond to changes in hydrological conditions, such as successive drying and rewetting periods. As peatlands are rich in organic matter, any major changes in water table may influence the decomposition of it. The hydrological conditions may also influence release of nutrients from peat profiles as well as affect their transport to downstream ecosystems. In our mesocosm experiment, artificial water table fluctuations in pristine peat profiles caused an increase in dissolved organic nitrogen (DON) and ammonium(NH4+-N)concentrations, while no response was found in drained peat profiles, although originating from the same peatland complex.

Nitrogen Uptake, Dissolved Organic Nitrogen Release, and New Production

Science ◽  
1994 ◽  
Vol 265 (5180) ◽  
pp. 1843-1846 ◽  
Author(s):  
D. A. Bronk ◽  
P. M. Glibert ◽  
B. B. Ward
Keyword(s):  
Nitrogen Uptake ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Nitrogen Release ◽  
New Production

Dissolved Organic Nitrogen Release and Bacterial Activity in the Upper Layers of the Atlantic Ocean

2006 ◽  
Vol 51 (4) ◽  
pp. 487-500 ◽  
Author(s):  
Marta M. Varela ◽  
Antonio Bode ◽  
Xosé Anxelu G. Morán ◽  
Joaquín Valencia
Keyword(s):  
Atlantic Ocean ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Bacterial Activity ◽  
Nitrogen Release
Sign in / Sign up

Export Citation Format

Share Document