Dataset: Doliolid diet: CTD casts

Name: CTD downcasts from R/V Savannah SAV-15-10, SAV-15-19, SAV-15-31 in the South Atlantic Bight, Mid-Continental Shelf from May to December 2015 (Doliolid Diet project)
Published: 2017-05-01
Keywords: oceans

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Cite This Dataset

Spatial Extent: N:31.54934 E:-80.2083 S:29.945 W:-80.64218

Temporal Extent: 2015-05-19 - 2015-12-02

Project:

The cryptic diet of the globally significant pelagic tunicate Dolioletta gegenbauri (Uljanin, 1884.) (Doliolid Diet)

Principal Investigator:

Marc E. Frischer (Skidaway Institute of Oceanography, SkIO)

Co-Principal Investigator:

Deidre M. Gibson (Hampton University)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2017-05-01

Restricted:

Validated:

Current State:

Preliminary and in progress

CTD downcasts from R/V Savannah SAV-15-10, SAV-15-19, SAV-15-31 in the South Atlantic Bight, Mid-Continental Shelf from May to December 2015 (Doliolid Diet project)

Abstract:

CTD downcasts from R/V Savannah SAV-15-10, SAV-15-19, SAV-15-31 in the South Atlantic Bight, Mid-Continental Shelf from May to December 2015. Data from 2016 and 2017 will be added once validated.

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Description

This dataset includes CTD data from 23 casts in water depth of 25 to 40 meters from three cruises in May, August and December 2015 on the RV/Savannah to the South Atlantic Bight. In addition to salinity, conductivity, temperature and depth, also reported are light, fluorescence, oxygen saturation and nitrogen saturation.

Methods & Sampling

CTD sampling methodology is standardized by the marine technician and crew of the UNOLS vessel R/V Savannah. Down-cast and up-cast winch speed is maintained at 25 m/min unless sea conditions require alteration. The CTD is deployed to 2 to 1.5m above the surface of the bottom to minimize benthic influences on the water samples and the possibility of damaging the instruments. All water samples are collected in Niskin bottles are retrieved on the upcast after allowing the CTD to equilibrate at the desired depth for at least 30 seconds. Data from the CTD carousel is archived to an onboard Server running Windows Server 2012 at 4 hz as hex files with header and bottle files. The software used to control the CTD is Seaterm and Seasave.

Data quality control is monitored in real time during each cast by comparing surface salinity and temperature to the thermosalinograph data. Sensors are maintained to manufacture specifications and calibrated as specified by the manufacturer or as needed if anomaly’s or drift is observed. The precision and accuracy of the data is dependent on the limitation of each individual sensor and the rate of change in depth of the CTD through the water column vs. the frequency of data collection. For a list of the sensors used: deployed sensors. Data is provided to the chief scientist from the ship as raw data at the end of each research deployment.

Data Processing Description

Raw CTD data was accessed using the SBE Data Processing software (ver 7.23.2, Sea-Bird Electronics, Inc.). The data conversion feature of the software was used to convert the raw hex data to an ascii format. For each CTD cast, data was converted only from the scans that were made during the down casts of the CTD deployments. Scans were stored as converted data files (.cnv). A total of 22 variables were converted from the CTD scans and included location, time, depth, temperature, salinity, and conductivity parameters. Microsoft Excel was used to archive the converted data. No further data processing was performed on the converted files.

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 columns for cruise id, cast, lat_start, lon_start. date, time obtained from CTD cast headers

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1459293
NSF Division of Ocean Sciences	OCE-1459510

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
SAV-15-10	DolDiet_001	2015-05-19	R/V Savannah	Marc E. Frischer (Chief Scientist) Deidre M. Gibson (Co-Chief Scientist)	data info
SAV-15-19	DolDiet_002	2015-08-03	R/V Savannah	Marc E. Frischer (Chief Scientist) Deidre M. Gibson (Co-Chief Scientist)	data info
SAV-15-31	DolDiet_003	2015-12-01	R/V Savannah	Marc E. Frischer (Chief Scientist)	data info

Instruments

Sea-Bird SBE 25 Sealogger CTD

Supplied Name: Sea-Bird 25

Supplied Description:

temp_sn, cond_sn, Real-Time Sample, Interval (sec)
SAV_15-10, 2336, 1909, 0.25
SAV_15-19, 2336, 1909, 0.25
SAV-15-31, 2684, 2868, 0.25

Instrument Type

Generic Name: Sea-Bird SBE 25 Sealogger CTD

Acronym: CTD SBE 25

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0040/

Generic Description:

The Sea-Bird SBE 25 SEALOGGER CTD is battery powered and is typically used to record data in memory, eliminating the need for a large vessel, electrical sea cable, and on-board computer. All SBE 25s can also operate in real-time, transmitting data via an opto-isolated RS-232 serial port. Temperature and conductivity are measured by the SBE 3F Temperature sensor and SBE 4 Conductivity sensor (same as those used on the premium SBE 9plus CTD). The SBE 25 also includes the SBE 5P (plastic) or 5T (titanium) Submersible Pump and TC Duct. The pump-controlled, TC-ducted flow configuration significantly reduces salinity spiking caused by ship heave, and in calm waters allows slower descent rates for improved resolution of water column features. Pressure is measured by the modular SBE 29 Temperature Compensated Strain-Gauge Pressure sensor (available in eight depth ranges to suit the operating depth requirement). The SBE 25's modular design makes it easy to configure in the field for a wide range of auxiliary sensors, including optional dissolved oxygen (SBE 43), pH (SBE 18 or SBE 27), fluorescence, transmissivity, PAR, and optical backscatter sensors. More information from Sea-Bird Electronics: http:www.seabird.com.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	cruise identifier	unitless	cruise_id
cast	cast number	unitless	cast
lat_start	cast starting latitude; north is positive	decimal degrees	lat_start
lon_start	cast ending longitude; east is positive	decimal degrees	lon_start
date	UTC date	unitless	date
time_start	UTC time at start of cast	unitless	time_start
Depth1_m	depth	meters	depth
Depth2_m	depth of water?	meters	depth_w
Latitude_deg	latitude; north is positive	decimal degrees	lat
Longitude_deg	longitude; east is positive	decimal degrees	lon
Salinity_PSU	salinity	PSU	sal
Temperature_C	temperature	degrees Celsius	temp
Voltage_0	output of 1st voltage sensor	volts	no_bcodmo_term
Conductivity_uS_cm	conductivity	microSiemens/cm	cond
Conductivity_mS_cm	conductivity	milliSiemens/cm	cond
Conductivity_S_m	conductivity	Siemens/m	cond
Density_kg_m3	density	kilograms/m^3	density
Density_sigma_theta_kg_m3	potential density which takes into account adiabatic heating/cooling with changes in pressure	kilograms/m^3	sigma_theta
Density_sigma_t_kg_m3	potential density	kilograms/m^3	sigma_t
Density_sigma_1_kg_m3	potential density	kilograms/m^3	no_bcodmo_term
Density_sigma_2_kg_m3	potential density	kilograms/m^3	no_bcodmo_term
Descent_Rate_m_s	descent rate of CTD	meters/sec	descent_rate
Fluorescence_mg_m3	fluorescence WET Labs WETstar	milligram/meter^3	fluor
Fluorescence_2_mg_m3	fluorescence WET Labs WETstar	milligram/meter^3	fluor
Fluorescence_Diff2_1_mg_m3	fluorescence WET Labs WETstar difference of second from first reading	milligram/meter^3	fluor
Time_Elapsed_min	time elapsed since start of cast	minutes	time_elapsed
Voltage_1	output of 2nd voltage sensor	volts	no_bcodmo_term
Voltage_2	output of 3rd voltage sensor	volts	no_bcodmo_term
Voltage_3	output of 4th voltage sensor	volts	no_bcodmo_term
Voltage_4	output of 5th voltage sensor	volts	no_bcodmo_term
PAR	Photosynthetically Available [Active] Radiation; downwelling irradiance; Biospherical/Licor	microEinsteins/m^2 sec	PAR
Oxygen_pcent_sat	oxygen saturation: the ratio of calculated oxygen to oxygen saturation	percent	O2_sat_pcnt
Nitrogen_Saturation_mg_l	nitrogen saturation: the theoretical saturation limit of the water at the local temperature and salinity value but with local pressure reset to zero (1 atmosphere)	milligrams/liter	no_bcodmo_term
Acceleration_m_s2	acceleration of CTD through water	meter/second^2	no_bcodmo_term
flag	quality flag; 0 = ok?	unitless	flag

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Dataset: Doliolid diet: CTD casts