Zooplankton abundance from ring net tows from RVIB Nathaniel B. Palmer NBP1801 in the Ross Sea, January 2018

Website: https://www.bco-dmo.org/dataset/789299
Data Type: Cruise Results
Version: 1
Version Date: 2020-02-05

Project
» Using Bio-acoustics on an Autonomous Surveying Platform for the Examination of Phytoplankton-zooplankton and Fish Interactions in the Western Ross Sea (bio-acoustic plankton surveys)
ContributorsAffiliationRole
Saba, GraceRutgers UniversityPrincipal Investigator
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Net tows were conducted during the R/V Nathaniel B. Palmer cruise NBP18-01 in January 2018. These data represent the zooplankton species and abundance analysis resulting from these sample collections. A companion dataset of mid-water trawls abundances is also available.


Coverage

Spatial Extent: N:-74.8033 E:165.7405 S:-75.0042 W:164.4441
Temporal Extent: 2018-01-10 - 2019-01-31

Dataset Description

Net tows were conducted during the R/V Nathaniel B. Palmer cruise NBP18-01 in Jan-Feb 2018. These data represent the zooplankton species and abundance analysis resulting from these sample collections. A companion dataset of mid-water trawls abundances is also available.


Acquisition Description

Sample collection: Net tows and mid-water trawls were conducted in the western Ross Sea, Antarctica on board the R/V Nathaniel B. Palmer in January-February 2018 (cruise number 18-01). Both the ring net (1 m diameter, 333 um mesh, non-filtering cod end) and the Issacs-Kidd Midwater Trawl (IKMT, 1.8 m frame, 500 um mesh, non-filtering cod end) were fitted with a calibrated General Oceanics flow meter. Contents of each tow were concentrated and preserved with buffered formaldehyde (4% final concentration) in 500 ml wide-mouth glass jars. Samples were sent back to the home laboratory (Rutgers University) for analysis.

Analyses: Contents of each tow (or a subsample if the density of zooplankton or fish was high) were sorted by taxa and, in some cases, developmental stage. Measurements for abundance were conducted using a dissecting microscope (Zeiss Discovery.V8).

Volume of water (cubic meter) that passed through the net/trawl during each tow was calculated using flowmeter rotor constant, flowmeter start and end values, and the area of net opening.

Abundance per cubic meter per tow/trawl was then calculated for each species and, in some cases, developmental stage, by dividing the number of individuals for each species/developmental stage by the volume of water.


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
- in Method column, replaced commas with semicolons
- two columns were named 'Latitude end'; renamed second one 'Longitude end' as it's clearly a longitude.
- converted latitudes and longitudes to decimal degrees
- reformated date and times to ISO-format (from m/d/yy to yyyy-mm-ddTHH:MM:SSZ)
- changed commas in 'Method' column to semi-colons
- Corrected mis-spelled taxa:

  • Oithoha similis -> Oithona similis
  • Calanus simulus -> Calanus simillimus
  • Pareuchaeta antarctica -> Paraeuchaeta antarctica
  • Gaidus tenuispinus -> Gaidius tenuispinus
  • Heterohabdum -> Heterorhabdus
  • Pelagchia longicirrata -> Pelagobia longicirrata
  • Schyphomedusa -> Scyphomedusa

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Parameters

ParameterDescriptionUnits
MethodCollection method specified; either a 1-m diameter ring net with 333um mesh or an Isaacs Kidd Midwater Trawl with a 1.8-m frame unitless
Tow_Trawl_numberTow/Trawl number provided in chronological order during the cruise unitless
Date_UTCSampling date; UTC unitless
ISO_DateTime_UTC_startUTC date and time the tow/trawl started; ISO formatted: YYYY-MM-DDTHH:MM:SSZ unitless
ISO_DateTime_UTC_endUTC date and time the tow/trawl ended; ISO formatted: YYYY-MM-DDTHH:MM:SSZ unitless
lat_start_decdegLatitude/Location where the tow/trawl started decimal degrees
lon_start_decdegLongitude/Location where the tow/trawl started decimal degrees
lat_end_decdegLatitude/Location where the tow/trawl ended decimal degrees
lon_end_decdegLongitude/Location where the tow/trawl ended decimal degrees
Net_depth_mWater depth the ring net or trawl were towed meters
Bottom_depth_mWater depth at location of tow/trawl meters
SST_deg_CSea Surface Temperature at time and location of tow/trawl Degrees Celsius
Flowmeter_startCalibrated General Oceanics flowmeter reading at start of tow/trawl; used in calculations for water volume that passed through the net/trawl unitless
Flowmeter__endCalibrated General Oceanics flowmeter reading at end of tow/trawl; used in calculations for water volume that passed through the net/trawl unitless
Volume_m3Volume of water that passed through the net/trawl; calculated using flowmeter data and area of net opening cubic meters
Copepods_Calanoides_acutusAbundance of Calanoides acutus number/meter^3
C_acutus_CIII_to_VAbundance of Calanoides acutus stages CIII to V number/meter^3
Metridia_gerlacheiAbundance of Metridia gerlachei number/meter^3
Oithona_similisAbundance of Oithona similis number/meter^3
Calanus_simillimusAbundance of Calanus simillimus number/meter^3
Paraeuchaeta_antarcticaAbundance of Paraeuchaeta antarctica number/meter^3
Oncaea_spAbundance of Oncaea sp. number/meter^3
Gaidius_tenuispinusAbundance of Gaidius tenuispinus number/meter^3
Heterorhabdus_spAbundance of Heterorhabdus sp. number/meter^3
Unspecified_NaupliiAbundance of unspecified nauplii number/meter^3
Euphausiids_Euphausia_crystallorophiasAbundance of Euphausia crystallorophias number/meter^3
Thysanoessa_macruraAbundance of Thysanoessa macrura number/meter^3
Decapods_Notocrangon_antarcticusAbundance of Notocrangon antarcticus number/meter^3
Amphipods_Themisto_gaudichaudiiAbundance of Themisto gaudichaudii number/meter^3
Hyperoche_spAbundance of Hyperoche sp. number/meter^3
Vibilia_stebbingiAbundance of Vibilia stebbingi number/meter^3
Pteropods_Limacina_rangiiAbundance of Limacina rangii number/meter^3
Clione_limacina_antarcticaAbundance of Clione limacina antarctica number/meter^3
Polychaeta_Pelagobia_longicirrataAbundance of Pelagobia longicirrata number/meter^3
Polychaete_larvaeAbundance of polychaete larvae number/meter^3
Fish_Pleuragramma_antarctica_larvaeAbundance of Pleuragramma antarctica larvae number/meter^3
Pleuragramma_antarctica_juvenileAbundance of Pleuragramma antarctica juveniles number/meter^3
ChannichthyidaeAbundance of Channichthyidae number/meter^3
ArtedidraconidaeAbundance of Artedidraconidae number/meter^3
Other_OstracodsAbundance of other ostracods number/meter^3
ChaetognathaAbundance of Chaetognatha number/meter^3
CtenophoraAbundance of Ctenophora number/meter^3
ScyphozoaAbundance of Scyphozoa number/meter^3
SiphonophoreAbundance of Siphonophora number/meter^3
SalpidaeAbundance of Salps number/meter^3


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Instruments

Dataset-specific Instrument Name
ring net
Generic Instrument Name
Ring Net
Dataset-specific Description
Plankton net with 1 m diameter, 333 um mesh, non-filtering cod end. Used to collected zooplankton during the Ross Sea cruise.
Generic Instrument 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).

Dataset-specific Instrument Name
Zeiss Discovery V8 Dissecting microscope
Generic Instrument Name
Microscope-Optical
Dataset-specific Description
Optical microscope with magnification for observation of the Ross Sea cruise tow/trawl samples. Used to taxonomically identify and count collected zooplankton during the Ross Sea cruise.
Generic Instrument Description
Instruments that generate enlarged images of samples using the phenomena of reflection and absorption of visible light. Includes conventional and inverted instruments. Also called a "light microscope".

Dataset-specific Instrument Name
Isaacs-Kid Midwater Trawl
Generic Instrument Name
Isaacs-Kidd Midwater Trawl
Dataset-specific Description
Rectangle framed net (1.75 m x 1.44 m) with 500 um mesh and a non-filtering cod end. Used to collected zooplankton during the Ross Sea cruise.
Generic Instrument Description
A trawl with a pentagonal mouth opening and a dihedral depressor vane as part of the mouth opening. IKMTs come in various dimensions (refer to individual dataset documentation). The original IKMTs were 10 foot (304 cm) and 15 foot (457 cm) at the mouth. The 10 foot IKMT net was 31 feet (9.45 m) in length (Wiebe and Benfield 2003).


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Deployments

NBP1801

Website
Platform
RVIB Nathaniel B. Palmer
Start Date
2017-12-16
End Date
2018-03-03
Description
Chief Scientist: Saba, Grace Start Port: Punta Arenas End Port: Hobart


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Project Information

Using Bio-acoustics on an Autonomous Surveying Platform for the Examination of Phytoplankton-zooplankton and Fish Interactions in the Western Ross Sea (bio-acoustic plankton surveys)

Coverage: Terra Nova Bay, Western Ross Sea, Antarctica


NSF Award Abstract: The Ross Sea is the one of the most productive regions in Antarctica and supports large populations of several key species in the Ross Sea food web, including copepods, crystal krill (Euphausia crystallorophias), and Antarctic silverfish (Pleuragramma antarcticum). Copepods and crystal krill dominate the diets of Antarctic silverfish, the dominant fish species in the high Antarctic zone, and silverfish are a major link between lower (copepods, krill) and higher (fishes, marine mammals, flighted birds, Adélie and Emperor penguins) trophic levels. Despite the significance of these key species, there is limited understanding of copepod, krill, and silverfish mesoscale distribution, spatial structure of age/maturity classes, and their interactions with physical drivers within the Ross Sea. Autonomous underwater profiling gliders are a developing technology that offers the potential for providing high spatial, temporal, and depth resolution data on regional scales. The project will test the capability of a multi-frequency echo sounder integrated into a Slocum Webb glider with the aim of providing the first glider-based acoustic assessment of simultaneous distributions of three trophic levels in the Ross Sea. Complementary glider sensors measuring physical, chemical, and biological parameters will provide mesoscale and sub-mesoscale hydrographic information from which phytoplankton-zooplankton-fish interactions and the relationships between these organisms and physics drivers (sea ice, circulation features) will be investigated. The approach proposed here, glider acoustics, is relatively new and has the potential to be transformational for investigating food webs and the Ross Sea ecosystem. Researchers will modify and integrate an Acoustic Zooplankton and Fish Profiler (AZFP) multi-frequency echo sounder into a Slocum Webb G2 glider with the capability to differentiate between krill and other types of zooplankton, including copepods, and different sizes of krill and silverfish. The AZFP will be complemented with the existing glider sensors including a CTD, a WET Labs BB2FL ECO puck configured for simultaneous chlorophyll fluorescence (phytoplankton biomass) and optical backscatter measurements, and an Aanderaa Optode for measuring dissolved oxygen. The new sensor suite will be tested during a four-week glider deployment, where it will conduct acoustic surveys to map distribution and abundance of multiple zooplankton taxa and silverfish during the austral summer along the Terra Nova Bay polynya ice shelf and in adjacent continental shelf waters. The relationships between phytoplankton-zooplankton-fish distributions and the physical drivers of zooplankton and silverfish species and size distributions will be investigated. Coordinated ship-based acoustic sampling and net tows/trawls will be conducted multiple times during the glider deployment to validate glider acoustic-based species, size, and abundance measurements. Open accessible, automated data produced during this project will be made available through RUCOOL (Rutgers University Center for Ocean Observing Leadership) and THREDDS (Thematic Real-time Environmental Data Distribution System). The production of consistent, vertically-resolved, high resolution glider-based acoustic measurements will define a successful outcome of this project that should help in identifying the challenges in their use as a potentially cost-effective, automated examination of food webs in the Antarctic.


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Funding

Funding SourceAward
NSF Office of Polar Programs (formerly NSF PLR) (NSF OPP)

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