Chlorophyll fluorescence and turbidity backscatter data from Groves Creek salt marsh, Skidaway Island Georgia, USA, 2013-2015

Website: https://www.bco-dmo.org/dataset/682753
Data Type: Other Field Results
Version: 1
Version Date: 2017-02-21

Project
» Tempo and mode of salt marsh exchange (GrovesCreek)
ContributorsAffiliationRole
Savidge, WilliamSkidaway Institute of Oceanography (SkIO)Principal Investigator
Brandes, JaySkidaway Institute of Oceanography (SkIO)Co-Principal Investigator
Edwards, CatherineSkidaway Institute of Oceanography (SkIO)Co-Principal Investigator
Stubbins, AronSkidaway Institute of Oceanography (SkIO)Co-Principal Investigator
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Chlorophyll fluorescence and turbidity backscatter were measured at two stations in Groves Creek salt marsh, Skidaway Island Georgia, USA from July 2013 to March 2015.


Coverage

Spatial Extent: Lat:31.97 Lon:-81.02
Temporal Extent: 2013-07-26 - 2015-03-11

Methods & Sampling

Chlorophyll and turbidity sampling: Chlorophyll fluorescence and turbidity backscatter at S2 and S8 were measured with Wetlabs FLNTUSB shuttered fluorometers. The deployment scheme for the FLNTUSB units was identical to that for the YSI and FLCDs.  The YSIs, FLCD and FLNTUSB fluorometers were swapped out on the same schedules.  At S2, the fluorometers were also mounted below the “moon pool” of the floating dock and were ~ 1m from the YSIs.   At S8, they were collocated on the bottom frame with the other instruments.


Data Processing Description

Chlorophyll and turbidity data processing.
Raw turbidity backscatter and chlorophyll fluorescence counts have been converted to NTUs (nepthelometric turbidity unit) and chlorophyll concentration (ug chl l-1) units using the manufacturer calibration sheets that were provided with the instruments (Supplemental Files). No other processing has yet been done with the turbidity data. The instrument response was regularly saturated under the turbid conditions found in Groves Creek.  Chlorophyll data have been processed analogously to the fDOM data . While the chlorophyll data are likely to be “right” in a relative sense, the absolute value of the sonde readings underestimate in situ chlorophyll obtained from extracted samples by a factor of 2-3.  The data provided here are for the factory calibrations.  Third-part users can use the data found in the manufacturer calibration sheet to make an empirical correction, while cautioning that most of the water samples were collected for analysis of chlorophyll at high tide.  The contributions of turbidity and CDOM interference with the raw sonde signals have been examined.  No significant contribution by either variable were revealed using multiple linear regression.

BCO-DMO Processing notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- added station, lat, lon, date, time, ISO_DateTIme columns
- ISO Date format generated from date and time values
- blank values replaced with no data value 'nd'


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Data Files

File
fluor.csv
(Comma Separated Values (.csv), 10.47 MB)
MD5:49b9a16b07510b4b6aaefa5c994cbbe4
Primary data file for dataset ID 682753

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Supplemental Files

File
Field chlorophyll data (CSV)
filename: CHL_cal_data.csv
(Comma Separated Values (.csv), 16.78 KB)
MD5:fa669e26bab8c498f6909975a1ea5b42
Field data that support the empirical sonde calibrations. Included in this file are the factory calibration values for each sonde deployed across the channel.
Field chlorophyll data (XLSX)
filename: CHL_cal_data.xlsx
(Microsoft Excel, 48.27 KB)
MD5:a563a086af2f03655739b636466e3160
Field data that support the empirical sonde calibrations. Included in this file are the factory calibration values for each sonde deployed across the channel.
Groves Creek station
filename: S2_S8_stations.csv
(Comma Separated Values (.csv), 843 bytes)
MD5:a73d14f479effe359fdadd0115456ae1
Locations and deployment dates for stations S2 and S8
Sonde factory calibration data (CSV)
filename: sonde factory cals.csv
(Comma Separated Values (.csv), 1.41 KB)
MD5:9be3173f0b25cc5939504ad15a4dc940
Chlorophyll concentration (ug chl l-1) units using the manufacturer calibration sheets that were provided with the instruments.
Sonde factory calibration data (XLSX)
filename: sonde_factory_cals.xlsx
(Octet Stream, 15.66 KB)
MD5:68156b2b50d7ad05c164c3c74e6ad5fa
Chlorophyll concentration (ug chl l-1) units using the manufacturer calibration sheets that were provided with the instruments.

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Parameters

ParameterDescriptionUnits
station

station identifier

unitless
lat

latitude; north is positive

decimal degrees
lon

longitude; east is positive

decimal degrees
date

UTC date formatted as yyyy-mm-dd

unitless
time

UTC time; formatted as hh:mm

unitless
ISO_DateTime_UTC

Date/Time (UTC) ISO formatted based on ISO 8601:2004(E) with format YYYY-mm-ddTHH:MM:SS[.xx]Z

unitless
deployment

deployment number

unitless
datenum_matlab

MATLAB formatted datenum

unitless
chl_ref

monitor of internal battery output (refer to the appropriate Wetlabs manuals for a full description.)

unitless (volts/volts)
chl_counts

digitized voltages of chlorophyll counts relative to a full scale instrument response of 4000 counts (itself representative of some maximum voltage)

unitless (volts/volts)
NTU_ref

monitor of internal battery output (refer to the appropriate Wetlabs manuals for a full description)

unitless (volts/volts)
NTU_counts

digitized voltages of turbidity counts relative to a full scale instrument response of 4000 counts (itself representative of some maximum voltage)

unitless (volts/volts)
thermistor

voltage output from a temperature sensor: not used in this study

volts
sonde_id

sonde instrument identifier

unitless
chl_a

concentration of chlorophyll a

micrograms/liter (ug/l)
turbidity

turbidity

Nephelometric Turbidity Units (NTU)


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Instruments

Dataset-specific Instrument Name
Wetlabs FLNTUSB shuttered fluorometers
Generic Instrument Name
Fluorometer
Generic Instrument Description
A fluorometer or fluorimeter is a device used to measure parameters of fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. The instrument is designed to measure the amount of stimulated electromagnetic radiation produced by pulses of electromagnetic radiation emitted into a water sample or in situ.


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Deployments

Groves_Creek_2013-2015

Website
Platform
Groves Creek - SkIO
Start Date
2013-07-26
End Date
2015-03-11
Description
Studies of temporal and compositional changes in exported material in a saltmarsh, both the quantity and quality of dissolved organic matter (DOM) and particulate organic matter (POM) exported from Groves Creek.


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Project Information

Tempo and mode of salt marsh exchange (GrovesCreek)


Coverage: Salt marsh east of Savannah, Georgia, USA.


Description from NSF award abstract:
Salt marshes are critical mediators of the flux of material between the terrestrial and marine realms. The balance of material import, export, and transformation affects both the marsh itself and the surrounding estuary. Previous efforts to understand the role of marshes have concentrated either on examining temporal changes (often at low resolution) of bulk exports, or compositional changes in exported material with little regard for its temporal variability. Researchers working at the Skidaway Institute of Oceanography contend that both the quantity and quality of materials exchanged between marsh and estuary in tidally-dominated systems along the southeastern US coast vary significantly in response to semidiurnal, diurnal, tidal, meteorological and seasonal forcing, and that this variability must be included when considering the total contributions of marshes to carbon cycling along the land-ocean boundary. This study will utilize a three-pronged strategy to assess both the quantity and quality of dissolved organic matter (DOM) and particulate organic matter (POM) exported from Groves Creek, a well-characterized meso-tidal salt marsh in coastal Georgia. In particular, by evaluating how marsh function responds to a full spectrum of present environmental conditions, this project will provide tangible insight into how carbon cycling in these critical regions will respond to anticipated changes in those conditions.

This project is related to the project "Marine priming effect - molecular mechanisms for the biomineralization of terrigenous dissolved organic matter in the ocean" found at https://www.bco-dmo.org/project/554157.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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