CTD Hydrocasts were performed with a Sea-Bird SBE 9 mounted near the base of a Niskin 24 Bottle Rosette.
|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.|
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.
The CTD data were processed with Seasave v. 7.18.
- 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.
Station identifier; a unique number or alphanumeric string designating a general geographic location at which one or more sampling activities may occur.
Latitude at start of cast.
latitude at start time of measurement; in decimal degrees (negative denotes South)
Longitude at start of cast.
longitude at starting time of measurement (west is negative), in decimal degrees
date sampling starts such as YYYYMMDD
starting time of observation, GMT time, 24 hour clock
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)
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.
2009-08-30T14:05:00[.xx]Z (UTC time)
Pressure. Originally named 'PrDM'.
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.
conductivity, from the CTD 'secondary sensor', usually reported in Siemens/meter. Depending on input source may have a variety of names.
Beam transmission from Chelsea/Seatech/Wetlab Cstar. Originally named 'Xmiss'.
light transmission, as percent
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 is the cloudiness or haziness of a fluid caused by individual particles
potential temperature (International Practical Temperature Scale - 68 ,or 90). When known, the scale will be reported in the units field of the documentation file.
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.
dissolved oxygen concentration
|Steven L. D’Hondt||University of Rhode Island (URI-GSO)||✓|
|David C. Smith||University of Rhode Island (URI-GSO)|
|Robert Pockalny||University of Rhode Island (URI-GSO)|
|Arthur J. Spivack||University of Rhode Island (URI-GSO)|
|Shannon Rauch||Woods 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|
|Created||November 8, 2011|
|Modified||January 18, 2012|
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.
|Steven L. D’Hondt||University of Rhode Island (URI-GSO)||Principal Investigator|
|David C. Smith||University of Rhode Island (URI-GSO)||Co-Principal Investigator|
|Robert Pockalny||University of Rhode Island (URI-GSO)||Co-Principal Investigator|
|Arthur J. Spivack||University of Rhode Island (URI-GSO)||Co-Principal Investigator|