Inorganic and organic nutrient data from Niskin bottles from R/V Knorr cruise KN210-04 in the Western Atlantic Ocean between Uruguay and Barbados in 2013 (Deep Atlantic DOM project)

Website: https://www.bco-dmo.org/dataset/473296
Data Type: Cruise Results
Version: 1
Version Date: 2016-07-25

Project
» Dissolved Organic Matter Composition in the Deep Atlantic Ocean (Deep Atlantic DOM)

Program
» Ocean Carbon and Biogeochemistry (OCB)
ContributorsAffiliationRole
Kujawinski, ElizabethWoods Hole Oceanographic Institution (WHOI)Principal Investigator
Longnecker, KristaWoods Hole Oceanographic Institution (WHOI)Co-Principal Investigator, Contact
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Inorganic and organic nutrient data from Niskin bottles from the KN210-04 cruise. Data include concentration of: phosphate, nitrate+nitrite, silicate, nitrite, ammonium, non-purgeable organic carbon, and total nitrogen.


Coverage

Spatial Extent: N:9.700333 E:-24.000749 S:-38.0026 W:-55.299424
Temporal Extent: 2013-03-27 - 2013-05-06

Dataset Description

Inorganic and organic nutrient data from Niskin bottles from the KN210-04 cruise. Data include concentration of: phosphate, nitrate+nitrite, silicate, nitrite, ammonium, non-purgeable organic carbon, and total nitrogen.


Acquisition Description

Samples for inorganic nutrient analysis were collected in HDPE bottles and frozen (-20ºC) immediately after sample collection. Samples were kept frozen until processing by Joe Jennings at Oregon State University. The analyses for phosphate (PO4), nitrate plus nitrite (NO3_NO2), nitrite (NO2), ammonium (NH4), and silicic acid (silicate) were performed using a hybrid Technicon AutoAnalyzerII and Alpkem RFA300 system following protocols modified from Gordon et al. (see below for reference). The estimated precision for each element was as follows: PO4, ± 0.008 µM; NO3_NO2, ± 0.15 µM; NO2, ± 0.01 µM; silicic acid, ± 0.3 µM.

To obtain the concentration of total organic carbon (TOC) and total nitrogen (TN), a 40 ml aliquot of whole seawater was acidified to pH~3 with concentrated hydrochloric acid (HCl) and stored in combusted glass vials at 4°C until analysis with a Shimadzu TOC-VCSH total organic carbon analyzer coupled to a TNM-1 analyzer. Blanks (MilliQ water) and standard curves with potassium hydrogen phthalate and potassium nitrate were interspersed into the sample runs. The coefficient of variability between replicate injections was <1%. Comparisons to standards provided by Prof. D. Hansell (University of Miami) were made daily.

References:
Gordon, L. I., J. C. Jennings, Jr., A. A. Ross, and J. M. Krest. 1994. A suggested protocol for continuous flow automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic Program and the Joint Global Ocean Fluxes Study. In WOCE operations manual. WOCE report no. 68/91, revision 1. WHP Office Report WHPO91-1. Woods Hole Oceanographic Institution, Woods Hole, Mass.


Processing Description

The data have been examined to identify outliers, and no samples were removed from the dataset. There are values in the inorganic nutrient data which are below zero, and these should be considered as below the detection limit for the instrument.

BCO-DMO Processing Notes:
- Parameter names were modified to conform with BCO-DMO naming conventions.
- lat_start and lon_start were added by joining the data to the event log and matching on the unique event number.
- Replaced 'NaN' with 'nd' to indicate 'no data'.
- Replaced questionable NPOC value for cast 18, niskin 21 with 'nd' per request of PI (change made on 25 July 2016).


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Parameters

ParameterDescriptionUnits
castConsecutive cast number for the instrument. dimensionless
stationIdentification number of the sampling station. dimensionless
date_start_utcDate (UTC) given as 4-digit year -- 2-digit month -- 2-digit day in YYYYmmdd format. unitless
time_start_utcTime (UTC) given as hour -- minute. HHMM
event_startThe event number from the ELOG maintained during the cruise. dimensionless
lat_startLatitude at the time the event started (from the cruise event log). decimal degrees
lon_startLongitude at the time the event started (from the cruise event log). decimal degrees
niskinNiskin bottle number. dimensionless
depthDepth. meters (m)
pressPressure. decibars (db)
botsThe full range of Niskin bottles used for the sample collection. For this particular dataset this is equal to the Niskin number. dimensionless
PO4Phosphate. micromoles per liter (umol/L)
NO3_NO2Nitrate + nitrite. micromoles per liter (umol/L)
silicateSilicate. micromoles per liter (umol/L)
NO2Nitrite. micromoles per liter (umol/L)
NH4Ammonium. micromoles per liter (umol/L)
NPOCNon-purgeable organic carbon. micromolar (uM)
TNTotal nitrogen. micromolar (uM)


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Instruments

Dataset-specific Instrument Name
Niskin bottle
Generic Instrument Name
Niskin bottle
Generic Instrument 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.

Dataset-specific Instrument Name
Shimadzu TOC-V
Generic Instrument Name
Shimadzu TOC-V Analyzer
Dataset-specific Description
The concentrations of total organic carbon (TOC) and total nitrogen (TN) were determined with a Shimadzu TOC-VCSH total organic carbon analyzer coupled to a TNM-1 analyzer.
Generic Instrument Description
A Shimadzu TOC-V Analyzer measures DOC by high temperature combustion method.

Dataset-specific Instrument Name
Technicon AutoAnalyzerII
Generic Instrument Name
Technicon AutoAnalyzerII
Dataset-specific Description
The analyses for phosphate (PO4), nitrate plus nitrite (NO3_NO2), nitrite (NO2), ammonium (NH4), and silicic acid (silicate) were performed using a hybrid Technicon AutoAnalyzerII and Alpkem RFA300.
Generic Instrument Description
A rapid flow analyzer that may be used to measure nutrient concentrations in seawater. It is a continuous segmented flow instrument consisting of a sampler, peristaltic pump, analytical cartridge, heating bath, and colorimeter. See more information about this instrument from the manufacturer.

Dataset-specific Instrument Name
Alpkem RFA300
Generic Instrument Name
Alpkem RFA300
Dataset-specific Description
The analyses for phosphate (PO4), nitrate plus nitrite (NO3_NO2), nitrite (NO2), ammonium (NH4), and silicic acid (silicate) were performed using a hybrid Technicon AutoAnalyzerII and Alpkem RFA300.
Generic Instrument Description
A rapid flow analyser (RFA) that may be used to measure nutrient concentrations in seawater. It is an air-segmented, continuous flow instrument comprising a sampler, a peristaltic pump which simultaneously pumps samples, reagents and air bubbles through the system, analytical cartridge, heating bath, colorimeter, data station, and printer. The RFA-300 was a precursor to the smaller Alpkem RFA/2 (also RFA II or RFA-2).


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Deployments

KN210-04

Website
Platform
R/V Knorr
Start Date
2013-03-25
End Date
2013-05-09
Description
Western Atlantic cruise started at Montevideo, Uruguay and ended at Bridgetown, Barbados. Science Objectives: 1. Characterize deep ocean dissolved organic matter in water masses of western Atlantic Ocean. 2. Characterize microbial community at selected stations and at selected depths. 3. Characterize metabolic capabilities of surface, mesopelagic and bathypelagic microbial consortia vis-a-vis the degradation of organic matter from each zone. 4. Examine metabolic and phylogenetic links between microbes in different marine zones (surface, meso-pelagic and bathypelagic depths). Science Activities: 1. Collection of discrete water samples by Niskin-bottles. 2. Collection of microbial communities from these water samples, by in-situ pumping, or by net-traps and net-tows. 3. Incubation experiments in lab and on deck. 4. Underway mass spectrometry and flow cytometry, from seawater intake. More information is available from the WHOI Cruise Planning Synopsis. Additional cruise information and original data are available from the NSF R2R Data Catalog.


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Project Information

Dissolved Organic Matter Composition in the Deep Atlantic Ocean (Deep Atlantic DOM)

Coverage: Western Atlantic Ocean


Transformations of dissolved organic matter (DOM) in the deep ocean have profound impacts on the global carbon cycle due to the sequestration of carbon dioxide (CO2) away from the atmosphere. Although research has been conducted on the high molecular weight component of this material, the same cannot be said for low molecular weight DOM because the needed analytical techniques have not been available to determine its composition and reactivity.

In recent years, a research team at Woods Hole Oceanographic Institution has acquired the necessary analytical capability. As such, in this project, they will carry out the first systematic survey of deep ocean DOM in the western Atlantic Ocean to characterize the low molecular weight fraction of DOM in southward flowing North Atlantic Deep Water (NADW), northward flowing Antarctic Bottom Water (AABW), and Antarctic Intermediate Water (AAIW). Using ultrahigh resolution mass spectrometry and multi-stage fragmentation coupled to liquid chromatography, the scientists will determine the spatial variability in the composition of DOM along the flow path of the water masses, as well as assess the source water, transport, and surface processes that contribute to temporal changes in DOM composition. These results will be augmented with structural elucidation and quantitative assays of unique marker compounds for each water mass. Results will provide important insights into the biogeochemical reactions that govern DOM dynamics in the deep ocean.



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Program Information

Ocean Carbon and Biogeochemistry (OCB)


Coverage: Global


The Ocean Carbon and Biogeochemistry (OCB) program focuses on the ocean's role as a component of the global Earth system, bringing together research in geochemistry, ocean physics, and ecology that inform on and advance our understanding of ocean biogeochemistry. The overall program goals are to promote, plan, and coordinate collaborative, multidisciplinary research opportunities within the U.S. research community and with international partners. Important OCB-related activities currently include: the Ocean Carbon and Climate Change (OCCC) and the North American Carbon Program (NACP); U.S. contributions to IMBER, SOLAS, CARBOOCEAN; and numerous U.S. single-investigator and medium-size research projects funded by U.S. federal agencies including NASA, NOAA, and NSF.

The scientific mission of OCB is to study the evolving role of the ocean in the global carbon cycle, in the face of environmental variability and change through studies of marine biogeochemical cycles and associated ecosystems.

The overarching OCB science themes include improved understanding and prediction of: 1) oceanic uptake and release of atmospheric CO2 and other greenhouse gases and 2) environmental sensitivities of biogeochemical cycles, marine ecosystems, and interactions between the two.

The OCB Research Priorities (updated January 2012) include: ocean acidification; terrestrial/coastal carbon fluxes and exchanges; climate sensitivities of and change in ecosystem structure and associated impacts on biogeochemical cycles; mesopelagic ecological and biogeochemical interactions; benthic-pelagic feedbacks on biogeochemical cycles; ocean carbon uptake and storage; and expanding low-oxygen conditions in the coastal and open oceans.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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