[Location: Location_Category='OCEAN', Location_Type='INDIAN OCEAN', Location_Subregion1='ARABIAN SEA']
Nitrogen-15 Uptake, F-ratio, Ammonium Concentration, and Low-level Nitrate Concentration Measured during the U.S. JGOFS Arabian Sea Process StudyEntry ID: USJGOFS_ARAB_NITROGEN_UPTAKE
Abstract: A component of U.S. Joint Global Ocean Flux Study (JGOFS) is the
Arabian Sea Process Study. Eleven cruises took place aboard the R/V
Thomas G. Thompson for about sixteen months from October 1994 until
January 1996. These cruises provided seasonal coverage of the annual
monsoon and inter-monsoon cycles in the area southeast of Oman - from
... where the cruises were staged. The monsoons of the Arabian Sea drive
a uniquely intense carbon cycling system, and it is the goal of JGOFS
to better understand the role of the oceans in global carbon cycling.
Biological uptake of nitrogen was determined by labeling substrates
with nitrogen-15. Water samples were obtained with the trace
metal-clean rosette bottle sampler.
Depth profiles of nitrogen-15 uptake rates are available for nitrite
(NO2) labeled substrate, nitrate (NO3) labeled substrate, and
ammonium (NH4) labeled substrate. N-15 uptake rate units are in nMol
Areal summary data reflect corrections to the profile data and a
reassessment of the diel cycle for nitrogen uptake. The profile data
are integrated (1% Io) daily to create the areal summary. Units for
nitrogen-15 uptake areal summaries are in mMol N /m^2/day.
F-ratio data are calculated as follows: pNO3/(pNO2+pNO3+NH4), where p
is the N-15 uptake rate from the indicated substrate.
Depth profiles of ammonium concentration are also available. These
are high sensitivity data of ammonium in the euphotic zone, with a
detection limit of 0.002 micro molar.
Depth profiles of low-level (nanomolar range) nitrate concentrations
are also available.
The data is public domain and can be retrieved on-line at
[This information was obtained from U.S. JGOFS website at WHOI.]
(Click for Interactive Map)
Start Date: 1994-10-01Stop Date: 1996-01-31
Quality Due to the strong diel patterns in nitrogen uptake and the resulting
possible misinterpretation of the N-15 uptake profile data through
simple integration and daily mulitpliers, the user community is
directed to the areal summary N-15 uptake data.
Access Constraints The data are public domain and can be retrieved on-line from the
U.S. JGOFS World Wide Web server at WHOI.
Use Constraints Anyone wishing to use U.S. JGOFS data in a presentation, report,
thesis or publication should contact the originating PI. It is
expected that all customary courtesies and privileges attached to data
use will be strictly honored.
Data Set Progress
Distribution Media: Online
Email: CGarside at Bigelow.org
180 McKown Point, P.O. Box 475
City: West Boothbay Harbor
Province or State: ME
Postal Code: 04575-0475
Email: james_j_mccarthy at harvard.edu
Museum of Comparative Zoology Harvard University 26 Oxford Street
Province or State: MA
Postal Code: 02139
Nitrogen-15 uptake rate methodology found in:
McCarthy,J.J., Chris Garside, John L. Nevins and Richard T. Barber,
1996. New production along 140W in the equatorial Pacific during and
following the 1992 El Nino event. Deep Sea Research Part II, Vol.43,
No. 4-6, 1065-1093.
Ammonium concentration methodology found in:
Brzezinski (1988), Limnol. & Oceanog. 33: 1176-1182.
Low-level nitrate concentration methodology found in:
Garside C., 1982. A chemiluminescent technique for the determination
of nanomolar concentrations of nitrate and nitrite in seawater. Marine
Chemistry 11. 159-167.
Creation and Review Dates
Last DIF Revision Date: 2009-05-13