Dataset: Nitrate Uptake
Deployment: MV1008

15NO3 uptake, 24-hour in situ incubations.

Principal Investigator:

Michael R. Landry (University of California-San Diego, UCSD-SIO)

Contact:

Michael Stukel (University of Maryland Center for Environmental Science, UMCES/HPL)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Costa Rica Dome FLUx and Zinc Experiments (CRD FLUZiE)

Current State:

Final no updates expected

Version:

29 May 2014

Version Date:

2014-05-29

Data URL:

https://www.bco-dmo.org/dataset-deployment/516115/data

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Description

15NO3 uptake rates measured during experimental cycles on the MV1008 cruise in the Costa Rica Dome (CRD) region of the Eastern Tropical Pacific Ocean.

Methods & Sampling

Dataset acquisition description

15NO3- uptake rates were determined daily during experimental cycles from samples incubated on the in situ array at 8 depths spanning the euphotic zone. Each day samples were collected from Niskin rosette into polycarbonate bottles (a single 1.2-L bottle per depth). Samples were spiked with K15NO3 (final concentration 0.100 umol L-1). All samples were incubated in situ for 24 hours beginning and ending at ~04:00 am local time. Upon recovery, 5NO3 uptake samples were immediately filtered through pre-combusted GF/F filters at low pressure and frozen in liquid nitrogen. On land, they were thawed, acidified, dried out, and analyzed by mass spec at the SIO Analytical Facility.

Data Processing Description

Dataset Processing Description

Nitrate uptake was calculated following Dugdale and Wilkerson (1986). 15Ninit, 15Nfinal, 15Nnat, and 15Nspk were the 15:14N mass ratios for ambient PON in the water column (averaged for the cycle), final PON at the end of the incubation, water column NO3, and the K15NO3 spike, respectively. [NO3]nat was the water column nitrate values at the beginning of the incubation (determined from 0.1-um filtered, frozen samples analyzed at the UCSB Analytical Facility) and [15NO3]spk was the final concentration of added K15NO3 (0.1 umol L-1). Since [NO3]nat was not determined until the end of the cruise, the investigators used a fixed [15NO3]spk. The previous equation can significantly overestimate ambient nitrate uptake rates when [15NO3]spk is greater than 10% of [NO3]nat, so when this was determined to be the case, the investigators assumed that [NO3]nat was significantly than the half-saturation constant for NO3 and hence applied a correction such that ρcorrected=ρ×[NO3]nat/([NO3]nat+[NO3]spk).

BCO-DMO added lat and lon values from the MV1008 event log.

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0826626	NSF Division of Ocean Sciences

Instruments

Mass Spectrometer

Supplied Name: Mass Spec

Supplied Description:

Samples were analyzed by mass spec at the SIO Analytical Facility.

Instrument Type

Generic Name: Mass Spectrometer

Acronym: Mass Spec

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/

Generic Description:

General term for instruments used to measure the mass-to-charge ratio of ions; generally used to find the composition of a sample by generating a mass spectrum representing the masses of sample components.

Niskin bottle

Supplied Description:

Each day samples were collected from Niskin rosette into polycarbonate bottles.

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic Description:

A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
event	Number referring to the particular activity (event) on the FluZiE cruise.	integer	event
cast	CTD Cast number from the FluZiE cruise.	integer	cast
cycle	Refers to the 4-day Lagrangian experiment during which the sample was taken.	integer	no_bcodmo_term
date	Date of CTD cast from which the water for the incubation was drawn (local time zone of UTC -6). format: mmddyyyy	unitless	date
event_lat	Latitude (in degrees North); added by BCO-DMO from the MV1008 event log.	decimal degrees	lat
event_lon	Longitude (in degrees East); added by BCO-DMO from the MV1008 event log.	decimal degrees	lon
depth	Nominal depth (in meters) that the sample was taken from and incubated at.	meters	depth
sample	Refers to a specific 15NO3 uptake incubation measurement.	unitless	sample
nitrate	Ambient nitrate concentration of the initial water that was used for the incubation.	micromolar (uM)	NO3
NO3_uptake	NO3- uptake rate. See processing description for equations used.	micromoles N per liter per day (umol N L-1 d-1)	pNO3

Database

Contribute Data

Dataset: Nitrate Uptake
Deployment: MV1008

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Nitrate UptakeDeployment: MV1008

Dataset acquisition description

Dataset Processing Description

Dataset: Nitrate Uptake
Deployment: MV1008