Dataset: Krill densities
Deployment: CB1073

Depth-stratified krill net samples

View Data: For data, See Dataset Metadata Page: https://www.bco-dmo.org/dataset/842831

Principal Investigator:

Julie E. Keister (University of Washington, UW)

Contact:

Anna K. McLaskey (University of British Columbia , UBC-IOF)

BCO-DMO Data Manager:

Karen Soenen (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Consequences of hypoxia on food web linkages in a pelagic marine ecosystem (PelagicHypoxia)

Version:

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Description

Methods & Sampling

Dataset acquisition description

We sampled the density of all euphausiid life stages during dusk (within 1 hour of sunset) with a 60-cm diameter, 200-μm mesh ring net lifted vertically from 10 m off the bottom to the surface. We also characterized the nighttime density and vertical distribution of adult Euphausia pacifica using a 0.25 m2 Hydrobios MultiNet (five-net capacity) towed obliquely to collect depth-stratified samples. Flowmeters were used to monitor the volume of water filtered for all collections and samples were preserved in a 5% buffered formalin and seawater solution.

Data Processing Description

Dataset Processing Description

In the laboratory, samples from the vertical tows were quantitatively diluted to 4–10 times their settled volume and 2–3 subsamples were taken with a 1-mL Stempel pipette to quantify early life stages. In addition, one 10 mL Stempel pipette subsample was evaluated for any stages not found in the smaller subsamples. Euphausiid life stages were identified and classified as nauplius, calyptopis, furcilia, or juvenile/adult. All euphausiids from vertical tows were classified regardless of species, and a small portion may have been the sub-dominant species Thysannoessa raschii. Euphausiids from the oblique tows that were larger than 10 mm total length were identified as E. pacifica, sexed, and measured. Samples that contained > 30 large euphausiids were split prior to analysis.

Densities (#/m3) were calculated by life stage from each net.

BCO-DMO processing notes:

Adjusted parameter names to comply with database requirements.
Converted date to ISO format.

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1154648	NSF Division of Ocean Sciences

Instruments

Flow Meter

Supplied Name: TSK flow meter

Supplied Description:

60-cm diameter, 200-μm mesh ring net with TSK flow meter

Instrument Type

Generic Name: Flow Meter

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/388/

Generic Description:

General term for a sensor that quantifies the rate at which fluids (e.g. water or air) pass through sensor packages, instruments, or sampling devices. A flow meter may be mechanical, optical, electromagnetic, etc.

MultiNet

Supplied Name: Hydrobios MultiNet

Supplied Description:

0.25 m2 Hydrobios MultiNet (five-net capacity)

Instrument Type

Generic Name: MultiNet

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/NETT0099/

Generic Description:

The MultiNet© Multiple Plankton Sampler is designed as a sampling system for horizontal and vertical collections in successive water layers. Equipped with 5 or 9 net bags, the MultiNet© can be delivered in 3 sizes (apertures) : Mini (0.125 m2), Midi (0.25 m2) and Maxi (0.5 m2). The system consists of a shipboard Deck Command Unit and a stainless steel frame to which 5 (or 9) net bags are attached by means of zippers to canvas. The net bags are opened and closed by means of an arrangement of levers that are triggered by a battery powered Motor Unit. The commands for actuation of the net bags are given via single or multi-conductor cable between the Underwater Unit and the Deck Command Unit. Although horizontal collections typically use a mesh size of 300 microns, mesh sizes from 100 to 500 may also be used. Vertical collections are also common. The shipboard Deck Command Unit displays all relevant system data, including the actual operating depth of the net system.

Ring Net

Supplied Name: Ring net

Supplied Description:

60-cm diameter, 200-μm mesh ring net with TSK flow meter

Instrument Type

Generic Name: Ring Net

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/22/

Generic Description:

A Ring Net is a generic plankton net, made by attaching a net of any mesh size to a metal ring of any diameter. There are 1 meter, .75 meter, .25 meter and .5 meter nets that are used regularly. The most common zooplankton ring net is 1 meter in diameter and of mesh size .333mm, also known as a 'meter net' (see Meter Net).

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
Date	Date sample was collected in ISO format (yyy-mm-dd)	unitless	date
Station	Station code where sampling occurred	unitless	sta_id
Latitude	Latitude of station	decimal degrees	lat
Longitude	Longitude of station	decimal degrees	lon
Net_Type	Gear type used for sampling	unitless	net
Mesh_Size	Size of mesh used in sampling (microns)	microns	net_mesh
Depth_Max	Maximum depth sampled (meters)	meters (m)	depth
Depth_Min	Minimum depth sampled (meters)	meters (m)	depth
Species	Species sampled	unitless	species
Life_History_stage	Description of life history stage of sample	unitless	stage
Density	density of species sampled	count per cubic meter	density
Start_time_tow	Start Time of the tow in ISO format (hh:mm)	unitless	time_begin

Database

Contribute Data

Dataset: Krill densities
Deployment: CB1073

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Krill densitiesDeployment: CB1073

Dataset acquisition description

Dataset Processing Description

Dataset: Krill densities
Deployment: CB1073