Dataset: zooplankton dispvols MOC GoMaine
Deployment: EN484

Zooplankton displacement volumes from MOCNESS tows in the Gulf of Maine

Principal Investigator:

Gareth Lawson (Woods Hole Oceanographic Institution, WHOI)

Co-Principal Investigator:

Peter H. Wiebe (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

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

Project:

Biological and Physical Determinants of Euphausiid Aggregation, Behavior, and Interaction with Higher Predators at an Abrupt Topographical Feature in the Gulf of Maine (Krill GoME)

Current State:

Final no updates expected

Deployment Synonyms:

Krill

Version Date:

2013-01-06

Data URL:

https://www.bco-dmo.org/dataset-deployment/455750/data

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Description

Zooplankton displacement volumes from MOCNESS net tows in the Gulf of Maine in 2010.

Methods & Sampling

Dataset acquisition description

A standard 1m^2 Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) was used to collect zooplankton in order to determine the taxonomic composition of the zooplankton in the study region and also to ground truth acoustic data collected with the HTI multi-frequency and Edgetech broadband systems. The MOCNESS has 9 nets with a 335 µm mesh size that can sample different regions of the water column. The underwater unit used was #169.

In addition to the standard temperature and conductivity probes the system also had a beta-type strobe-light unit for reducing avoidance of the nets by some zooplankton, notably krill, and possibly small fish. The strobe system has two units each with 12 LED sets (LUXEON Rebel LED) with peak output between 490-520 nm. Two of the 24 LED sets were working inconsistently at the start of the sampling. The LEDs are powered by the MOCNESS battery and their pulse width, amplitude, flash rate period, and on/off are controlled by the MOCNESS software. For EN484, the pulse width was 2 ms, the relative amplitude was 99%, and the flash interval was 100 ms. For EN487, the pulse width was 40 ms, the relative amplitude was 99%, and the flash interval was 1000 ms.

The MOCNESS was launched and recovered from the stern A-frame. Samples were brought into the wet lab for processing. Net 0 typically went form the surface to depth and nets 1-8 fished at discrete depths from depth to the surface. Nets 1-8 were preserved in buffered formalin. Often the net 0 samples were so large that they would have taken multiple jars so either the entirety or a large fraction was frozen in the -80C freezer, in the hopes that they might be useful.

Displacement Volume Measurement:

Samples were poured into a 1000 ml graduated cylinders and measured. Then the sample was poured through a 330 um sieve, allowed to drain, and the volume of water measured. The difference between the two volume measurements was the displacement volume. The displacement volume of each sample was divided by the volume filtered by the net (m^3) and the result is reported here in units of cc/m^3. Animals larger than 5 cc were measured individually and reported here.

Data Processing Description

Dataset Processing Description

Related information:

Wiebe, P.H., K.H. Burt, S.H. Boyd, and A.W. Morton, A multiple opening-closing net and environmental sensing system for sampling zooplankton, J. Mar. Res., 34, 312-326, 1976.

Wiebe, P.H., A.W. Morton, A.M. Bradley, J.E. Craddock, T.J. Cowles, V.A. Barber, R.H. Backus, and G.R. Flierl, New developments in the MOCNESS, an apparatus for sampling zooplankton and micronekton, Mar. Biol., 87, 313-323, 1985.

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0928801	NSF Division of Ocean Sciences

Instruments

Hydroacoustic Technology Incorporated echosounder

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: Hydroacoustic Technology Incorporated echosounder

Acronym: HTI

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

Generic Description:

The Hydroacoustic Technology Inc. (HTI) multi-frequency system is a towed digital split-beam/single-beam hydroacoustic system designed specifically to assess the abundance and distribution of fish and plankton. Digital signal processing hardware is combined with a MS Windows2000/XP -based user interface to produce results in real time. (http://www.htisonar.com/multi_frequency_echo_sounder.htm)

MOCNESS

Supplied Description:

1m^2 MOCNESS with 9 nets, 330 micron mesh.

Instrument Type

Generic Name: MOCNESS

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/NETT0097/

Generic Description:

The Multiple Opening/Closing Net and Environmental Sensing System or MOCNESS is a family of net systems based on the Tucker Trawl principle. There are currently 8 different sizes of MOCNESS in existence which are designed for capture of different size ranges of zooplankton and micro-nekton Each system is designated according to the size of the net mouth opening and in two cases, the number of nets it carries. The original MOCNESS (Wiebe et al, 1976) was a redesigned and improved version of a system described by Frost and McCrone (1974).(from MOCNESS manual) This designation is used when the specific type of MOCNESS (number and size of nets) was not specified by the contributing investigator.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	cruise identification	alphanumeric	cruise_id
date	local date of tow	yyyymmdd	date
tow	MOCNESS tow number	integer	tow
site	location of tow	text	site
lat_start	latitude at start of cruise; north is positive	decimal degrees	lat_start
lon_start	longitude at start of cruise; east is positive	decimal degrees	lon_start
lat_end	latitude at end of cruise; north is positive	decimal degrees	lat_end
lon_end	longitude at end of cruise; east is positive	decimal degrees	lon_end
yrday_local	local day and decimal time; e.g. 326.5 for the 326th day of the year November 22 at 1200 hours (noon)	nd	yrday_local
time_local	local time	HHMM	time_local
day_night	whether cruise was taken in day or night	text	no_bcodmo_term
net	net number	integer	net
depth_range	depth range of sample	meters	depth_range
depth_open	depth where net opened	meters	depth_open
depth_close	depth where net closed	meters	depth_close
depth_mid	mid-depth of sample	meters	depth_mid
depth_interval	depth interval	meters	depth_interval
vol_filt	volume filtered by net	cubic meters	vol_filt
strobe	whether strobe light was firing while the net was open	text	no_bcodmo_term
disp_vol_m3	displacement volume per cubic meter	cc/meter^3	no_bcodmo_term
comments_sample	comments pertaining to the sample	text	no_bcodmo_term
zoop_gt5cc_id	identification of animals > 5cc	text	no_bcodmo_term
disp_vol_lg	displacement volume of large animals	cc	no_bcodmo_term
dominants	dominant zooplankton in the sample. An asterisk (*) means this species was especially abundant.	text	no_bcodmo_term

Database

Contribute Data

Dataset: zooplankton dispvols MOC GoMaine
Deployment: EN484

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: zooplankton dispvols MOC GoMaineDeployment: EN484

Dataset acquisition description

Dataset Processing Description

Dataset: zooplankton dispvols MOC GoMaine
Deployment: EN484