Dataset: HADES-K bacterial biomarker phospholipid fatty acid (PLFA)
Deployment: TN309

HADES-K bacterial biomarker phospholipid fatty acid (PLFA)

Principal Investigator:

Timothy M. Shank (Woods Hole Oceanographic Institution, WHOI)

Co-Principal Investigator:

Jeffrey C. Drazen (University of Hawaiʻi at Mānoa, SOEST)

Paul Yancey (Whitman College)

BCO-DMO Data Manager:

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

Project:

Controls on Hadal Megafaunal Community Structure: a Systematic Examination of Pressure, Food Supply, and Topography (HADES)

Deployment Synonyms:

HADES-K, HADESK

Data URL:

https://osprey.bco-dmo.org/dataset-deployment/763880/data

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Description

This dataset contains the sample log for HADESK bacterial biomarker phospholipid fatty acid (PLFA) content from sediment push cores. The same samples were also used for the organic matter (OM) analysis. Samples were taken in the Kermadec Trench in the Southwest Pacific, 4000 to ~10,000m from the RV/ Thomas G. Thompson during cruise TN309, May 2014.

Methods & Sampling

Dataset acquisition description

Push cores (6.35 cm diameter) of sediment were collected in situ using the manipulator arm of the Hybrid Remotely Operated Vehicle Nereus on the margin of the Kermadec Trench (6013m) and along the main trench axis (7137 to 9177m) at roughly 1000m increments.

Cores were sectioned at 1cm intervals and sieved for the meiofaunal fraction.

Upon retrieval of sediment cores, the 0-1, 1-2, 2-3, 3-5, 5-10 cm depth horizons were sectioned and stored frozen (-80 °C) until analysis. Benthic bacterial biomass were calculated from sediment concentrations of the bacterial biomarker phospholipid fatty acids (PLFAs) i14:0, i15:0, ai15:0, i16:0. In brief, PLFAs were extracted and purified from known quantities of freeze-dried sediment samples and subsequently derivatized to yield fatty acid methyl esters (FAMEs). FAMEs were quantified using GC-FID (Agilent Technologies 6890N). Bacterial biomass was calculated using the well-established PLFA:C conversion factor of 0.056 gC PLFA/gC biomass.

Attempts were made to obtain 3 replicate cores at each depth horizon (every 1000 meters from 6000m to 10,000m. For logistical reasons with vehicle performance (and loss at 10,000), all of the replicates were not able to be collected.

Data Processing Description

Dataset Processing Description

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- re-formatted date from m/d/yyyy to yyyy-mm-dd

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1131620	NSF Division of Ocean Sciences

Instruments

Elemental Analyzer

Supplied Name: Fisons NA 1500 elemental analyzer

Supplied Description:

Instrument Type

Generic Name: Elemental Analyzer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB01/

Generic Description:

Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.

HROV Nereus

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: HROV Nereus

Generic Description:

Nereus is an efficient, multi-purpose “hybrid” vehicle that can explore and operate in the crushing pressures of the greatest ocean depths. An unmanned vehicle, Nereus operates in two complementary modes. It can swim freely as an autonomous underwater vehicle (AUV) to survey large areas of the depths, map the seafloor, and give scientists a broad overview. When Nereus locates something interesting, the vehicle’s support team can bring the vehicle back on board the ship and transforms it into a remotely operated vehicle (ROV) tethered to the ship via a micro-thin, fiber-optic cable. Through this tether, Nereus can transmit high-quality, real-time video images and receive commands from skilled pilots on the ship to collect samples or conduct experiments with a manipulator arm.

Technical specifications:

Weight on land: 2,800 kg
Payload capacity: 25 kg
Maximum speed: 3 knots
Batteries: rechargable lithium ion, 15 kilowatt hours in two pressure housings
Thrusters: 2 fore and aft, 2 vertical, 1 lateral (ROV mode) 2 fore and aft, 1 vertical (AUV mode)
Lights: variable output LED array, strobes
Manipulator arm: Kraft TeleRobotics 7-function hydraulic manipulator
Sonar: scanning sonar, forward look and profile, 675 KHz
Sensors: magnetometer, CTD (to measure conductivity, temperature, and depth)

Nereus supports a variety of science operations: Push coring, measuring heat flow, geotechnical and geochemical sensing, rock sampling and drilling, biological sampling, water sampling, high resolution acoustic bathymetry, and optical still and video imagery.

More information is available from the operator site at URL.

Push Corer

Supplied Name:

Supplied Description:

Push cores were borrowed from the National Deep Submergence Facility to be able to standardize results. The push cores were 6.35cm diameter).

Instrument Type

Generic Name: Push Corer

Generic Description:

Capable of being performed in numerous environments, push coring is just as it sounds. Push coring is simply pushing the core barrel (often an aluminum or polycarbonate tube) into the sediment by hand. A push core is useful in that it causes very little disturbance to the more delicate upper layers of a sub-aqueous sediment.

Description obtained from: http://web.whoi.edu/coastal-group/about/how-we-work/field-methods/coring/

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
sample	sample identifier	unitless	sample
cruise_id	cruise identifier	unitless	cruise_id
dive	dive identifier	unitless	dive_id
site	site name	unitless	site
station	station identifier	unitless	station
core	core identifier	unitless	core_id
NiWa_id	National Institute for Water and Atmosphere identifier	unitless	sample
date_utc	sample collection date in UTC	unitless	date_utc
horizon_core_cm	depth horizon in core	centimeters	depth_core

Database

Contribute Data

Dataset: HADES-K bacterial biomarker phospholipid fatty acid (PLFA)
Deployment: TN309

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: HADES-K bacterial biomarker phospholipid fatty acid (PLFA)Deployment: TN309

Dataset acquisition description

Dataset Processing Description

Dataset: HADES-K bacterial biomarker phospholipid fatty acid (PLFA)
Deployment: TN309