Dataset: Optical Plankton Counter SOGLOBEC-OPC MOC

Name: Zooplankton data from the Optical Plankton Counter (OPC) on a MOCNESS from RVIB Nathaniel B. Palmer, ARSV Laurence M. Gould NBP0104, LMG0104, LMG0203, NBP0204 in the Southern Ocean from 2001-2002 (SOGLOBEC project)
Published: 2011-04-12
Keywords: oceans

Cite This Dataset

Spatial Extent: N:-65.184 E:-67.26 S:-69.717 W:-76.566

Project:

U.S. GLOBEC Southern Ocean (SOGLOBEC)

Program:

U.S. GLOBal ocean ECosystems dynamics (U.S. GLOBEC)

Principal Investigator:

Meng Zhou (University of Massachusetts Boston, UMB-EEOS)

Data Manager:

Yiwu Zhu (University of Massachusetts Boston, UMB-EEOS)

BCO-DMO Data Manager:

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

Version:

2011-04-12

Version Date:

2011-04-12

Validated:

Yes

Current State:

Final no updates expected

Zooplankton data from the Optical Plankton Counter (OPC) on a MOCNESS from RVIB Nathaniel B. Palmer, ARSV Laurence M. Gould NBP0104, LMG0104, LMG0203, NBP0204 in the Southern Ocean from 2001-2002 (SOGLOBEC project)

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2011-04-12	National Oceanographic Data Center (NODC)	0112189	2013-08-21

Description

This data set was collected from the Optical Plankton Counter (OPC, Focal Technologies) during Southern Ocean GLOBEC cruises LMG00104, NBP0104, LMG0203, and NBP0204. The OPC was mounted on the MOCNESS-1 frame.

Data Processing Description

The OPC data was processed into abundance spectra (N) vs. equivalent spherical diameter (ESD) of plankton in 50 size classes in the depth intervals of a correspondent MOCNESS-1 tow. The spectra calculation is based on the standard definitions in Zhou and Huntley (2007):

Definitions:

v = body volume of a zooplankter (1)
Water volume filtered (V) = OPC cross section × flow speed (2)
Abundancy sprectrum(N)= (# zooplankton in size interval delta_v)/ size interval delta_v * V (3)

Units:
ESD: mm
v: mm3
N: # mm-1 (?ESD) m-3 (water)
V: m3

Data file format:
Line 1 (header): latitude longitude date time (local, at the beginning of the deployment)
Line 2 (title): logESD dep-range1 dep-range2 ...
Line 3-52 (data): log10(ESD) log10(b) (dep 1) log10(b) (dep 2) ....

Notes:
1) Each data file represents one MOCNESS/OPC cast .The OPC failed in some MOCNESS tows.
2) The filename conventions are "CruiseName_spe_cntStationNumber.txt". The OPC cast number is same as the corresponding MOCNESS-1 cast number.
3) The depth intervals of abundance spectra are equal to the depth intervals of a corresponding MOCNESS tow.
4) The water filtered by the OPC was estimated using the flowmeter on the MOCNESS-1.
5) The size interval delta-v is evenly distributed on log(ESD) of valid OPC size range
6) The first column of the data file , represent the mid values of log10(ESD) of each size group.
7) The "-3.00" for log10(b) means 0 counts for the size group in the depth bin.
8) In some cases the OPC went through ups and downs in one depth bin, which are indicated in the depth range, for example, "25-22-75".

Reference:
Zhou, M. and M. E. Huntley, Population dynamics theory of plankton based on biomass spectra. Marine Ecology Progress Series, 157, 61-73, 1997.

Data Files

File
opc_moc1.csv (Comma Separated Values (.csv), 1.45 MB) MD5:d36178b5621c302ffdfac3b8019ba2f5 Primary data file for dataset ID 3466

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Antarctic Sciences	unknown SOGLOBEC NSF ANT

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
LMG0104	GLOBECI	2001-04-20	ARSV Laurence M. Gould	Dr Joseph J. Torres (Chief Scientist)	data info
LMG0203	GLOBECIII	2002-04-07	ARSV Laurence M. Gould	Dr Joseph J. Torres (Chief Scientist)	data info
NBP0104	GLOBECII	2001-07-22	RVIB Nathaniel B. Palmer	Peter H. Wiebe (Chief Scientist)	data info
NBP0204	GLOBECIV	2002-07-31	RVIB Nathaniel B. Palmer	Peter H. Wiebe (Chief Scientist)	data info

Instruments

MOCNESS

Supplied Description:

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.

Optical Plankton Counter

Supplied Description:

OPC mounted on MOCNESS-1 frame.

Instrument Type

Generic Name: Optical Plankton Counter

Acronym: OPC

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/352/

Generic Description:

An OPC provides quantitative measurements of abundance and sizes of mesozooplankton ranging between approximately 0.25 and 14 mm in Equivalent Spherical Diameter (ESD), and has the capability to integrate measurements from other sensors such as a CTD, fluorometer and Global Positioning System (GPS). It can be deployed on a variety of instruments such as SeaSoar, Aries, Scanfish, MOCNESS, a bongo net or simple towing frame. The data from an OPC are typically transmitted to a data acquisition computer through two conducting wires in a towing cable at real time, but it can also be modified to have an internal memory. Large amounts of data are produced. The procedures employed by OPC users vary from; i) estimating integrated biomass by integrating the OPC size distributions, ii) comparing size distributions between OPC and net samples, and iii) simply isolating a size region in the OPC size distribution which correspond solely to specific taxa, eg. Calanus spp..

from: Zhou, M., Tande, K., 2002. Optical Plankton Counter Workshop. GLOBEC Report 17, University of Tromso, Tromso

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
log_abund_spec	Log10 of the abundance spectra: zooplankton abundance per mm of ESD, per cubic meter of water, in log10	log10(number per millimeter/cubic meter of water)	no_bcodmo_term
cruiseid	cruise identifier	text	cruiseid
day_local	day in local time	1 to 30	day_local
depth_close	depth at which net closed	meters	depth_close
depth_open	depth at which net opened	meters	depth_open
lat	latitude; North is positive	decimal degrees	lat
logESD	log of the Estimated Spherical Diameter	millimeters	no_bcodmo_term
lon	longitude; East is positive	decimal degrees	lon
month_local	month in local time	1 to 12	month_local
time_local	local time; 24 hour clock	HHmm	time_local
tow	tow identifier	integer	tow
yrday_local	local day and decimal time; as 326.5 for the 326th day of the year or November 22 at 1200 hours (noon)	number	yrday_local
year	year of sampling, local time		year

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Database

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Dataset: Optical Plankton Counter SOGLOBEC-OPC MOC