Dataset: opc_ccs_nonzero
Deployment: T0205

OPC data where biomass values of 0 have been removed from display

Principal Investigator:

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

BCO-DMO Data Manager:

Ms Dicky Allison (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

U.S. GLOBEC Northeast Pacific (NEP)

Current State:

Final no updates expected

Version:

17 Oct 2012

Version Date:

2012-10-17

Data URL:

https://www.bco-dmo.org/dataset-deployment/455479/data

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Description

This dataset was derived from the opc_ccs_orig dataset. In the 'nonzero' dataset, values of 0 in the biomass column have been removed in order to allow the dataset to be mapped. See opc_ccs_orig or opc_ccs_alt for all data, including zeros.

U.S. GLOBEC Northeast Pacific California Current Program
Optical Plankton Counter (OPC) Data

Contact for this dataset is:
Meng Zhou
Dept. of Environmental, Coastal and Ocean Sciences
University of Massachusetts-Boston
Boston, MA 02125
Email: meng.zhou@umb.edu
Phone: 617-287-7419; Lab: 617-287-6186
FAX: 617-287-7474

This project addresses one of 3 central hypotheses of the U.S. GLOBEC Northeast Pacific (NEP) Study:
Spatial and temporal variability in mesoscale circulation constitutes the dominant physical forcing on zooplankton biomass, production, distribution, species interactions and retention and loss in coastal regions.(U.S. GLOBEC Northeast Pacific Implementation Plan, U.S. GLOBEC Report No. 17).

References:
Rodriguez, J. and M. M. Mullin. 1986. Relation between biomass and body weight of plankton in a steady state oceanic ecosystem. Limnol. Oceanogr., 31, 361-370.
Zhou, M. and M. E. Huntley. 1997. Population dynamics theory of plankton based on biomass spectra. Mar. Ecol. Prog. Ser., 157, 61-73.
Zhou, M. and K. S. Tande. 2002. Optical Plankton Counter workshop report. International Global Ocean Ecosystems Dynamics Program Report, No. 17, 67 pp.

For more Information about these data contact Dr. Zhou.

Last modified: June 29, 2006

Methods & Sampling

Dataset acquisition description

We attached an Optical Plankton Counter (see Zhou and Tande, 2002) to the OSU towed body (SeaSoar) to make 3-dimensional mesoscale surveys (in a 100-km-wide coastal region from Newport, Oregon to Crescent City, California) aimed at determining the distribution and productivity of zooplankton in relation to their physical environment. The OPC provides counts and size estimates of zooplankton sized particles that pass through the instrument. The OPC data with other data sets (e.g., acoustics; ADCP-derived velocities) collected on these surveys, and from companion ships doing net sampling of zooplankton will allow estimation of growth and mortality rates of zooplankton using the biomass spectra method (Zhou and Huntley, 1997).

Data Processing Description

Dataset Processing Description

The OPC-CCS data are organized on the GLOBEC server by transect within cruise. The master (level 0) page lists all of the cruises--there were two cruises in each of 2000 and 2002. Clicking on a cruise will show all of the casts collected and processed from that cruise (Level 1), along with the start date and time of the transect. Clicking on a cast will bring up the Level 2 file that shows OPC profile data. The raw data stream is averaged and output at every 4-m bin. The towed body undulates between a near-surface, shallow depth and a deeper depth (which hopefully is ABOVE the bottom). During normal ascent and descent rates of the SeaSoar, approx. 5-30 readings are averaged within every 4 m depth bin. At times of particularly slow depth change, more readings are included in these averages. Average latitude and longitude and date/time (GMT) for each depth bin are shown. OPC data for each reported depth bin include the total abundance of particles (no per m3), total carbon biomass (ug C/m3; estimated from equivalent spherical diameter (ESD) based on Rodriguez and Mullin (1986)), and a biomass spectrum (50 size classes of particles). The header for the biomass spectrum header (minimum of 0.33; maximum of 4.09) values are log10 based carbon intervals of individual particle size. There are 50 biomass size classes. The data for each of the spectra are the accumulated carbon of that size particle, normalized by the water volume, then normalized by the carbon interval, then expressed as log10 units. So the unit of biomass for each spectral class is log10(biomass spectrum (1/m3)).

Note 1: A fluorometer was interfaced with the OPC only for cruise NH0005. For all other cruises, the 'fluor' field value of 0.00 means 'no data'.

Note 2: Biomass spectrum contents: Header value of 0.33 means particles of ca. 10^0.33 = 2.138 ugC per particle. Largest particle size (header value 4.09 is particles of ca. 12302 ugC per particle.

Note 3: The original data contained values of '-99.00' to represent zero counts within any particular size (according to correspondence with Dr. Meng Zhou). BCO-DMO changed the '-99.00' values to '0.00' on 16 Oct 2012 so that they are not misinterpreted. However, biomass values of 0.00 have been removed from this version of the dataset. See opc_ccs_orig or opc_ccs_alt for all data, including zeros.

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0002257	NSF Division of Ocean Sciences
unknown NEP NOAA	National Oceanic and Atmospheric Administration

Instruments

Optical Plankton Counter

Supplied Description:

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

SeaSoar

Supplied Description:

Instrument Type

Generic Name: SeaSoar

Generic Description:

Towed, undulating vehicle usually equipped with a VPR, TAPS, PAR, CTD

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruiseid	Cruise ID	unitless	cruiseid
year	Year	unitless	year
transect	Transect Description	unitless	transect
start_month_gmt	Month of Transect Start (GMT)	unitless	month_start
start_day_gmt	Day of Transect Start (GMT)	unitless	day_start
start_time_gmt	Time of Transect Start (GMT)	unitless	time_start
elptime	Elapsed time from Start Time.	hours	time_elapsed
month_gmt	Month	unitless	month_gmt
day_gmt	Day	unitless	day_gmt
time_gmt	Time	unitless	time_gmt
lat	Latitude [decimal degrees]	decimal degrees	lat
lon	Longitude [decimal degrees]	decimal degrees	lon
depth	Depth of Observation [meters]	meters	depth
abundance	Total Abundance [counts/m3]	counts/m<sup>3</sup>	no_bcodmo_term
biomass_tot	Total Biomass [ug C/m3]	microgram C/meter^3	no_bcodmo_term
biovol	Total Biovolume [mm³/m³]	mm<sup>3</sup>/m<sup>3</sup>	no_bcodmo_term
fluor	Chlorophyll [mg/m³] See Note 1 below.	mg/m<sup>3</sup>	fluor
size_class	Smallest Size Class of biomass spectrum. (See Note 2 above, under 'Processing Description'.)		no_bcodmo_term
biomass	The data for each of the spectra are the accumulated carbon of that size particle, normalized by the water volume, then normalized by the carbon interval, then expressed as log10 units. So the unit of biomass for each spectral class is log10(biomass spectrum (1/m3)).		no_bcodmo_term

Database

Contribute Data

Dataset: opc_ccs_nonzero
Deployment: T0205

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: opc_ccs_nonzeroDeployment: T0205

Dataset acquisition description

Dataset Processing Description

Dataset: opc_ccs_nonzero
Deployment: T0205