Discrete data on hydrography (from CTD casts) and chemical analyses of dissolved nutrients and organic carbon on the Louisiana-Texas shelf in the Gulf of Mexico from R/V Pelican cruise 28 September – 11 October 2017

Website: https://www.bco-dmo.org/dataset/844721
Data Type: Cruise Results
Version: 1
Version Date: 2021-03-17

Project
» Collaborative Research: A RAPID response to Hurricane Harvey's impacts on coastal carbon cycle, metabolic balance and ocean acidification (HarveyCarbonCycle)
ContributorsAffiliationRole
Roberts, BrianLouisiana Universities Marine Consortium (LUMCON)Principal Investigator
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Discrete data on hydrography (from CTD casts) and chemical analyses of dissolved nutrients and organic carbon on the Louisiana-Texas shelf in the Gulf of Mexico from R/V Pelican cruise 28 September – 11 October 2017.


Coverage

Spatial Extent: N:29.641 E:-88.901 S:27.496 W:-95.309
Temporal Extent: 2017-09-28 - 2017-10-11

Dataset Description

Usage note: Time zone information was not received by BCO-DMO so it is unknown if the dates and times in this dataset are local or UTC. Please contact the dataset PI if you have questions about this.


Methods & Sampling

Conductivity, Temperature and Depth (CTD) data and water samples were collected at various depths across 102 stations (total n = 471) in the Gulf of Mexico on the R/V Pelican between September 28, 2017 and September 19, 2017. At all stations, a vertical profile of salinity, dissolved oxygen concentration and temperature was collected using a Seabird SBE 911 CTD instrument package mounted onto a rosette containing 12, 5L Niskin bottles for collecting aqueous samples at specific depths. Water samples were collected using a single Niskin bottle per depth and were analyzed across various analytical instruments for nutrient concentrations.

Water samples were collected using a single Niskin bottle per depth on the CTD rosette. Samples for dissolved inorganic nutrients and dissolved organic carbon / total nitrogen were analyzed following the methods detailed in Roberts and Doty (2015) and Mason et al. (2016). Specifically, one niskin bottle, water samples for dissolved inorganic nutrients (NO₃⁻ + NO₂⁻, NO₂⁻, PO₄³−, SiO₂, and NH₄⁺) were analyzed in duplicate using a Lachat Instruments QuikChem FIA+ 8000 Series Automated Ion Analyzer with an ASX-400 Series XYZ autosampler after being filtered through acid-cleaned (10% HCl), 47 mm diameter, 0.2 µm pore size, membrane filters (Pall SuporR-200) under low vacuum pressure. Samples were analyzed for dissolved NO₃⁻ + NO₂⁻ (by Cu-Cd reduction followed by azo dye colorimetry), PO₄³− (by the automated ascorbic acid reduction method), SiO₂⁻, and dissolved NH₄⁺ (by phenate colorimetry) (APHA, 1992). Dissolved NO₂⁻ was determined separately by azo dye colorimetry (without Cu−Cd reduction). Standard curves were prepared using certified standard stock solutions (Hach, Loveland CO) and yielded r² values of ≥ 0.999. NO₃⁻ concentration was determined by difference between NO₃⁻ + NO₂⁻ and NO₂⁻.

Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) concentrations were measured at least in triplicate on a Shimadzu TOC-VCSH Analyzer with TNM-1 Module (MDL 1.5 μmol C L−1, 0.3 μmol N L−1; Shimadzu Scientific Instruments, Columbia, MD) after being filtered through combusted (450°C), 47mm diameter Whatman GF/F filters under low vacuum pressure. Concentrations of dissolved organic nitrogen (DON) were determined by difference [DON=TDN−DIN].

All water chemistry data went through quality control checks. CTD instrument probes were calibrated prior to cruise departure.


Data Processing Description

CTD data were processed on Seabird's SBEDataProcessing-Win32.

BCO-DMO Processing:
- renamed fields to conform with BCO-DMO naming conventions.


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Data Files

File
oct_2017_discrete.csv
(Comma Separated Values (.csv), 84.75 KB)
MD5:a0375b3277142da3bac9d75e353fb128
Primary data file for dataset ID 844721

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Related Publications

APHA. 1992. Standard Methods for the Examination of Water and Wastewater, 18th Edn. Washington, DC : American Public Health Association.
Methods
Mason, O. U., Canter, E. J., Gillies, L. E., Paisie, T. K., & Roberts, B. J. (2016). Mississippi River Plume Enriches Microbial Diversity in the Northern Gulf of Mexico. Frontiers in Microbiology, 7. doi:10.3389/fmicb.2016.01048
Methods
Roberts, B. J., & Doty, S. M. (2015). Spatial and Temporal Patterns of Benthic Respiration and Net Nutrient Fluxes in the Atchafalaya River Delta Estuary. Estuaries and Coasts, 38(6), 1918–1936. doi:10.1007/s12237-015-9965-z
Methods

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Related Datasets

IsRelatedTo
Roberts, B. (2022) Discrete data on hydrography (from CTD casts) and chemical analyses of dissolved nutrients and organic carbon on the Louisiana-Texas shelf in the Gulf of Mexico from R/V Acadiana cruise 18-21 September 2017. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2021-03-10 doi:10.26008/1912/bco-dmo.844709.1 [view at BCO-DMO]

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Parameters

ParameterDescriptionUnits
Cruise

Cruise identification

unitless
Type

Type of cast (CTD)

unitless
DateTime

Date and time of sample collection

unitless
Date

Date of sample collection

unitless
Time

Time of sample collection

unitless
Station

Location of sample collection

unitless
Bottle_Depth

Depth of the sample bottle at collection

meters (m)
Longitude

Longitude, west is negative

decimal degrees North
Latitude

Latitude, south is negative

decimal degrees East
Seafloor_Depth

Depth of seafloor below water surface

meters (m)
Bottle

Bottle number on the CTD

unitless
Depth

Depth of CTD at sample collection

meters (m)
Temperature

CTD water temperature in degrees Celsius

degrees C
Salinity

CTD salinity in practical salinity units (PSU)

PSU
OxygenSBE

CTD dissolved oxygen concentration

micromoles per kilogram (umol/kg)
wetCDOM

wet colored dissolved organic matter concentration

milligrams per cubic meter (mg/m^3)
SPAR

surface photosynthetically active radiation

micromoles photons per square meter per second (umol/m2/s)
PAR

Photosynthetically active radiation

micromoles photons per square meter per second (umol/m2/s)
Turbidity

CTD turbidity in Formazin Turbidity Units (FTU)

FTU
NO3_NO2

Sample nitrate and nitrite concentration

micromoles per liter (umol N/L)
NO2

Sample nitrate concentration

micromoles per liter (umol N/L)
NO3_calculated

Calculated sample nitrate concentration

micromoles per liter (umol N/L)
NH4

Sample ammonium concentration

micromoles per liter (umol N/L)
DIN_calculated

Calculated dissolved inorganic nitrogen concentration

micromoles per liter (umol N/L)
PO4

Sample phosphate concentration

micromoles per liter (umol P/L)
SiO2

Sample silicate concentration

micromoles per liter (umol Si/L)
DOC

Sample dissolved organic carbon concentration

micromoles per liter (umol C/L)
TDN

Sample total dissolved nitrogen concentration

micromoles per liter (umol N/L)
DON_calculated

Calculated dissolved organic nitrogen concentration

micromoles per liter (umol N/L)


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Instruments

Dataset-specific Instrument Name
Sea-Bird SBE 911 CTD
Generic Instrument Name
CTD Sea-Bird 911
Dataset-specific Description
At all stations, vertical profiles were taken with the Sea-Bird SBE 911 CTD instrument package. The SBE 911 includes the SBE 9 Underwater Unit and the SBE 11 Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 and SBE 11 is called a SBE 911. The SBE 9 uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 and SBE 4). The SBE 9 CTD can be configured with auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.).
Generic Instrument Description
The Sea-Bird SBE 911 is a type of CTD instrument package. The SBE 911 includes the SBE 9 Underwater Unit and the SBE 11 Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 and SBE 11 is called a SBE 911. The SBE 9 uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 and SBE 4). The SBE 9 CTD can be configured with auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). More information from Sea-Bird Electronics.

Dataset-specific Instrument Name
Lachat Instruments QuikChem® FIA+ 8000 Series Automated Ion Analyzer
Generic Instrument Name
Flow Injection Analyzer
Dataset-specific Description
Water samples were analyzed for NO₃⁻ + NO₂⁻, NO₂⁻, PO₄³−, SiO₂, and NH₄⁺ using a Lachat Instruments QuikChem® FIA+ 8000 Series Automated Ion Analyzer with an ASX-400 Series XYZ autosampler.
Generic Instrument Description
An instrument that performs flow injection analysis. Flow injection analysis (FIA) is an approach to chemical analysis that is accomplished by injecting a plug of sample into a flowing carrier stream. FIA is an automated method in which a sample is injected into a continuous flow of a carrier solution that mixes with other continuously flowing solutions before reaching a detector. Precision is dramatically increased when FIA is used instead of manual injections and as a result very specific FIA systems have been developed for a wide array of analytical techniques.

Dataset-specific Instrument Name
5 L Niskin bottles
Generic Instrument Name
Niskin bottle
Dataset-specific Description
Water samples were collected from a rosette containing 12, 5L Niskin bottles that had the CTD instrument package mounted below it.  
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
Shimazdu Instruments TOC-VCSH and TNM-1
Generic Instrument Name
Total Organic Carbon Analyzer
Dataset-specific Description
Water samples were analyzed for dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) content using a Shimazdu Instruments TOC-VCSH and TNM-1 with attached ASI-V auto sampler.
Generic Instrument Description
A unit that accurately determines the carbon concentrations of organic compounds typically by detecting and measuring its combustion product (CO2). See description document at: http://bcodata.whoi.edu/LaurentianGreatLakes_Chemistry/bs116.pdf


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Deployments

PE18-11

Website
Platform
R/V Pelican
Start Date
2017-09-28
End Date
2017-10-11
Description
Additional cruise information is available from the Rolling Deck to Repository (R2R): https://www.rvdata.us/search/cruise/PE18-11


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Project Information

Collaborative Research: A RAPID response to Hurricane Harvey's impacts on coastal carbon cycle, metabolic balance and ocean acidification (HarveyCarbonCycle)

Coverage: Northwestern Gulf of Mexico


NSF Award Abstract:
Understanding how extreme events, like hurricanes, impact coastal ecosystems and the cycling of elements like carbon and oxygen, is important for improving our ability to predict how the global carbon cycle will respond to climate. This team of investigators, who have already been working together on understanding the carbon cycle in the Gulf of Mexico continental shelves, have important recent data against which to measure the effects of the passage of Hurricane Harvey in August, 2017. They will sample the waters and sediments of the northwestern Gulf of Mexico in September, October, and January to assess Harvey's impacts on a timescale of weeks to months.

The researchers pose three specific questions: 1. Will the region become a major source of carbon dioxide to the atmosphere, releasing carbon accumulated in the bottom water and sediments, and will this potential impact be faster and greater than during normal fall and winter mixing events? Will this process acidify the surface water and for how long? 2. Will the metabolic balance be substantially pushed toward net heterotrophy as a result of the storm in comparison to other years? 3. Can the amount of material delivered or redeposited across the continental shelf by a tropical cyclone be considerably larger than that related to winter storm systems? The PIs will measure water column nutrients, oxygen, organic carbon, and inorganic carbon system parameters; determine water column and benthic metabolic and nutrient flux rates; and sediment organic matter deposition rates. They will also collect end member river samples. They will compare the immediate (mid-Sept) but limited post-hurricane data and one-month post-hurricane, more detailed data with those collected in July and April to study the impacts of the storms. they will also compare 2017-2018 seasonal data to seasonal data over the same region collected in the past (2006-2008 and 2009-2010). They will also compare the impacts of Hurricane Harvey to those of Hurricanes Katrina and Rita (2005) and Tropical Storm Cindy (June 2017). The project will involve graduate and postdoctoral research and work to communicate results to the public.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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