URLhttps://www.bco-dmo.org/dataset/567276
Download URLhttps://www.bco-dmo.org/dataset/567276/data/download
Media Type text/tab-separated-values
Created September 17, 2015
Modified August 19, 2016
State Final no updates expected
Brief Description

CTD data from KN195-03 in the equatorial and north Pacific.

Acquisition Description

CTD Hydrocasts were performed with a Sea-Bird SBE 9 mounted near the base of a Niskin 24 Bottle Rosette. The CTD instrumentation included Conductivity (S/N 2186 & 2670), Temperature (ITS-90, S/N 4039 & 4195), Pressure (Digiquartz, S/N 785), Oxygen (SBE 43, S/N 0273), Fluorescence (Wetlab ECO-AFL/FL, S/N FLNTURTD-304), and Beam Transmission (Chelsea/Seatech/Wetlab CStar, S/N CST-1116DR). The data were processed with Seasave v. 7.18.

The downcast was conducted at 60 m per minute to a maximum depth of ~5 m above the seafloor (based on altimeter data). Features were selected from the downcast data for sampling on the upcast. These features included oxygen minimum layer(s), chlorophyll maximum layer(s) and the thermocline. In addition, standard depths of bottom, 50 m above bottom, 5000 m, 4000 m, 3000 m, 2000 m, 1500m, 1000m, 300m, 200m, 100 m, 50 m, 10 m, and surface were sampled.

Water samples were collected with a 24 bottle rosette with 10-L Niskin bottles. The water was filtered with flat membrane filters (Supor-200, 47-mm diameter, 0.2 µm P/N 60301) were placed into Swinex filter holders and attached to the petcock valve of the Niskin bottles with 1/4″ tubing. The valves were opened and the water was pushed through the filters with the compressed air. The filtration rate is ~200 ml per minute. Filtered water samples were collected for molybdenum and nitrogen isotopes. When the water stopped dripping through the filter, the filters were removed, folded in half and placed into a whirl-pak bag and stored at -70 degrees C in the lower lab freezer.

Processing Description

The CTD data were processed with Seasave v. 7.18.

BCO-DMO Processing:
– Modified parameter names to conform with BCO-DMO naming conventions;
– Obtained lat_start, lon_start, date_start, and time_start from the CTD file headers;
– Converted lat and lon to decimal degrees;
– Added ISO_DateTime_Start column.

Instruments

Sea-Bird SBE 9 [CTD Sea-Bird 9]
Details
Instance Description (Sea-Bird SBE 9)

CTD Hydrocasts were performed with a Sea-Bird SBE 9 mounted near the base of a Niskin 24 Bottle Rosette.

The Sea-Bird SBE 9 is a type of CTD instrument package. The SBE 9 is the Underwater Unit and is most often combined with the SBE 11 Deck Unit (for real-time readout using conductive wire) when deployed from a research 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, fluorometer, altimeter, etc.). Note that in most cases, it is more accurate to specify SBE 911 than SBE 9 since it is likely a SBE 11 deck unit was used. more information from Sea-Bird Electronics

Parameters

cruise_id [cruise_id]
Details
cruise_id
Cruise identification number.
cruise designation; name
station [station]
Details
station
Station identification number.

Station identifier; a unique number or alphanumeric string designating a general geographic location at which one or more sampling activities may occur.

cast [cast]
Details
cast

Cast number.

cast or profile number

date_start [date_start]
Details
date_start
Date (YYYYmmdd) at start of cast.

date sampling starts such as YYYYMMDD

time_start [time_start]
Details
time_start
Time (HH:MM:SS) at start of cast.

starting time of observation, GMT time, 24 hour clock

ISO_DateTime_Start [ISO_DateTime_UTC]
Details
ISO_DateTime_Start
Date and time at start of cast, formatted to ISO8601 standard.

Date/Time (UTC) ISO formatted
This standard is based on ISO 8601:2004(E) and takes on any of the following forms:
2009-08-30T09:05:00[.xx] (local time)
2009-08-30T14:05:00[.xx]Z (UTC time)
2009-08-30T14:05:00[.xx]-05:00
The dashes and the colons can be dropped.
The T can also be dropped "by mutual agreement", but one needs the trailing Z if the time is UTC.

Sample ISO_datetime_utc:
2009-08-30T14:05:00[.xx]Z (UTC time)

Format: YYYY-mm-ddTHH:MM:SS[.xx]Z (UTC time)
press [pressure]
Details
press

Pressure. Originally named 'PrDM'.

water pressure at measurement; depth reported as pressure; positive number increasing with water depth
temp [temperature]
Details
temp
Temperature, ITS-90 (primary). Originally named 'T090C'.
water temperature at measurement depth
temp2 [temp2]
Details
temp2
Temperature, ITS-90 (secondary). Originally named 'T190C'.
temperature, as observed by a CTD unit, 'secondary sensor', may be ITS 68 or 90 scale; When known, the temperature scale is reported in the units field of the doc file in degrees Celsius. Depending on the input source the temperature from the secondary sensor can have a variety of names i.e. t1, t2, temp1, temp2, temp_S. Change to DMO term temp2
cond [conductivity]
Details
cond
Conductivity (primary). Originally named 'C0S/m'.

Conductivity.  Units and collection methods may vary.  Often reported in Siemens/meter.

When used in a JGOFS/GLOBEC project this is the conductivity in Siemens/meter for the primary conductivity sensor on a CTD.

cond2 [cond2]
Details
cond2
Conductivity (secondary). Originally named 'C1S/m'.

conductivity, from the CTD 'secondary sensor', usually reported in Siemens/meter. Depending on input source may have a variety of names.

O2_volt [O2_v]
Details
O2_volt
Oxygen voltage from SBE43. Originally named 'Sbeox0V'.
Oxygen voltage
bean_trans [transmission]
Details
bean_trans

Beam transmission from Chelsea/Seatech/Wetlab Cstar. Originally named 'Xmiss'.

light transmission, as percent

fluor [fluorescence]
Details
fluor
Fluorescence from Wetlab ECO-AFL/FL. Originally named 'FlECO-AFL'.

Fluorescence. Indirect measure of pigment concentration.

Units and collection method may vary. Units often reported in milligrams/meter^3 (mg/m3) or micromoles per liter (ug/L). Sometimes reported after being calibrated against extracted pigment concentrations.

In JGOFS/GLOBEC projects fluorescence is measured from CTD instrument sensor.

turbidity [turbidity]
Details
turbidity
FLNTU turbidity. Originally named 'Upoly0'.

Turbidity is the cloudiness or haziness of a fluid caused by individual particles

density [density]
Details
density
Density (primary). Originally named 'Density00'.

density, in mass per unit volume

density2 [density]
Details
density2
Density (secondary). Originally named 'Density11'.

density, in mass per unit volume

sigma_t [density]
Details
sigma_t
Sigma-t density (primary). Originally named 'Sigma-t00'.

density, in mass per unit volume

sigma_t_2 [sigma-t]
Details
sigma_t_2
Sigma-t density (secondary). Originally named 'Sigma-t11'.

Sigma-t density, often reported in kg/m^3 - 1000. 'Sigma-t' is density minus 1000 (without the effect of pressure). It is normally calculated from observations of temperature and salinity. (See How do we measure the density of sea water?)

potemp [potemp]
Details
potemp
Potential temperature, ITS-90 (primary). Originally named 'Potemp090C'.

potential temperature (International Practical Temperature Scale - 68 ,or 90). When known, the scale will be reported in the units field of the documentation file.

Details
potemp2
Potentential temperature, ITS-90 (secondary). Originally named 'Potemp190C'.
potential temperature (International Practical Temperature Scale - 68 ,or 90) from secondary sensor. When known, the scale will be reported in the units field of the documentation file.
sal [sal]
Details
sal
Salinity (primary). Originally named 'Sal00'.

salinity, calculated from the CTD 'primary sensors' of conductivity and temperature, Practical Salinity Scale (PSS-78), dimensionless. Depending on the input source, salinity from the primary sensors can have a variety of names i.e. s0, s00, sal0, sal00.

sal2 [sal2]
Details
sal2
Salinity (secondary). Originally named 'Sal11'.
salinity, calculated from the CTD 'secondary sensors' of conductivity and temperature, Practical Salinity Scale, dimensionless. Depending on the input source, salinity from the secondary sensors can have a variety of names including s1, s2, s11, s22, sal1, sal2, sal22, sal_S.
O2_pcnt_sat [O2_sat_pcnt]
Details
O2_pcnt_sat
Oxygen percent saturation from SBE43. Originally named 'Sbeox0PS'.
Saturation of oxygen in the water body, as a percentage.
Details
O2
Oxygen from SBE43. Originally named 'Sbeox0Mm/Kg'.

dissolved oxygen concentration

sal_diff [Salinity_difference]
Details
sal_diff
Salinity difference (sal2 - sal). Originally named 'SecS-priS'.
For Seabird 911 CTDs, salinity difference derived from Secondary Temperature/Conductivity sensor pair minus Primary Temperature/Conductivity sensor.
cond_diff [unknown]
Details
cond_diff
Conductivity difference (cond2 - cond). Originally named 'T2-T190C'.
association with a community-wide standard parameter is not yet defined
soud_vel [sound_vel]
Details
soud_vel

Sound velocity. Originally named 'SvWM'.

sound velocity in sea water, in meters/second

Dataset Maintainers

NameAffiliationContact
Steven L. D'HondtUniversity of Rhode Island (URI-GSO)
David C. SmithUniversity of Rhode Island (URI-GSO)
Robert PockalnyUniversity of Rhode Island (URI-GSO)
Arthur J. SpivackUniversity of Rhode Island (URI-GSO)
Shannon RauchWoods Hole Oceanographic Institution (WHOI BCO-DMO)

BCO-DMO Project Info

Project Title Oceanographic control and global distributions of subseafloor microbial life and activity
Acronym Subseafloor Microbial Life
URLhttps://www.bco-dmo.org/project/2182
Created November 8, 2011
Modified January 18, 2012
Project Description

Recent studies of subseafloor life, that is microbes living deep below the ocean&aposs seafloor, have produced astonishing results that challenge fundamental ideas about the limits and distributions of life. These include: (1) that the microbial biomass of subseafloor sediments is spatially much more variable and possibly much smaller than previously believed; (2) that rates of subseafloor sedimentary microbial activity are far below the rate required for cell maintenance, implying that either most subseafloor cells are inactive or that the energy required for their cellular maintenance is lower than anticipated; and (3) the global distributions of subseafloor sedimentary microbes and their activities are significantly affected by the oceanographic properties of the overlying water column. This proposal will conduct fieldwork to test these ideas at a range of sites in the equatorial Pacific. To do this the principal investigators will conduct a transect study where the following samples and measurements will be taken: (1) coring the sediment to ~18 meter or more below seafloor (mbsf) at 12 sites in the Pacific Ocean; (2) conducting extensive microbiological and biogeochemical analyses of these cores; (3) surveying the oceanographic and geologic characteristics of each site; and (4) using the results to test and refine models for the global distribution of subseafloor microbial abundances and their metabolic activities. Using these data the investigators will then address four important questions: (1) What are the principal controls on the magnitude and geographic distribution of subseafloor sedimentary cell abundance and steady-state rates of microbial activities? (2) Can we accurately estimate the magnitude and global distribution of subseafloor sedimentary cell abundance? (3) Can we accurately estimate the global distribution of organic carbon-fueled microbial activity in subseafloor sediment? and (4) Do different subseafloor sediments with very different cell abundances and rates of metabolic activity characterized by different groups of organisms? This study will significantly advance our understanding of life in the subseafloor ocean and will provide samples for diverse independent studies, including the International Census of Marine Microbes. This project will also have a strong research and training impact at both the graduate and undergraduate levels as the inherently multidisciplinary nature of subsurface life provides an ideal entry into collaborative modern science.

Data Project Maintainers
NameAffiliationRole
Steven L. D'HondtUniversity of Rhode Island (URI-GSO)Principal Investigator
David C. SmithUniversity of Rhode Island (URI-GSO)Co-Principal Investigator
Robert PockalnyUniversity of Rhode Island (URI-GSO)Co-Principal Investigator
Arthur J. SpivackUniversity of Rhode Island (URI-GSO)Co-Principal Investigator
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