MOCNESS summary data from Gulf of Maine krill cruises from R/V Endeavor, R/V Connecticut EN484, EN487, CT2010 in the Gulf of Maine, Georges Bank, Southern New England Shelf and Slope Water from 2010-2010 (Krill GoME project)

Website: https://www.bco-dmo.org/dataset/3402
Version: 12/29/2010
Version Date: 2010-12-29

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)
ContributorsAffiliationRole
Lawson, GarethWoods Hole Oceanographic Institution (WHOI)Principal Investigator
Wiebe, Peter H.Woods Hole Oceanographic Institution (WHOI)Co-Principal Investigator
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager


Dataset Description

Summary of environmental data collected by the MOCNESS system's (1 meter-square) electronics package.


Processing Description

Nov. 29, 2010:
Revised MOCNESS files for recomputed volumes using new flow meter calibration value determined on R/V Connecticut and R/V Endeavor (EN487). See write-up decribing the calibration procedure in EN487 cruise report. The volume revisions were done by Peter Wiebe using a flow meter calibration value of 6.41, which was the average of the values determined on the two cruises. The following is a list of the files used (raw) and produced (pro, tab) to compute the volumes filtered.

Date revised  Raw file Used      New Pro file    New Tab file
R/V Endeavor (EN484) Tows:
17Nov2010   M_01_1.raw        M001.pro          M001.tab
17Nov2010   M_1_002.raw      M002.pro          M002.tab
17Nov2010   M_01_003.raw    M003.pro          M003.tab
 Note: M_1_004.raw modified to eliminate extra headers due to restarts before tow actually started. 
17Nov2010   M_1_004.raw      M004.pro          M004.tab

R/V Endeavor (EN487) Tows:
17Nov2010   M_1_1.raw           M001.pro          M001.tab
17Nov2010   M_1_002.raw      M002.pro          M002.tab
17Nov2010   M_01_003.raw    M003.pro          M003.tab
  Note: M_1_004.raw modified to eliminate extra lines at start of tow. 
17Nov2010   M_1_004.raw      M004.pro          M004.tab
17Nov2010   M_01_005.raw    M005.pro          M005.tab

R/V Connecticut tows:
18Nov2010 - modified M_01_002.raw to eliminate start and end data when net out of the water and also removed the "#increment_net" indicator for net 2 because it apparently did not open at the 600 m mark. Net 8 was opened at the surface and taking out this indicator provides the volumes for the towing scenario indicated on the log sheets.
18Nov2010   M_1_002.raw      M002.pro          M002.tab
18Nov2010 - modified M_01_003.raw to eliminate end data when net out of the water and also modifed the "#increment_net" indicator in all cases so that the postprocessing would ignore the indicator. In addition all of the "+" indicators were changed to "-" to prevent spurious net number changes in the raw file from indicating a net bar had been dropped except that a "+" was added at the end of the raw file along with an "#increment_net" indicator to make the program calculate the total volume filtered for the tow. This was done because none of the nets were opened or closed on the tow. See log notes for additional details.
18Nov2010   M_1_003.raw      M003.pro          M003.tab
18Nov2010 - modified M_01_005 to eliminate end data when net out of the water and  a "+" was added at the end of the raw file along with an "#increment_net" indicator to make the program calculate the total volume filtered for the third net that was not closed at the surface.
18Nov2010   M_1_005.raw      M005.pro          M005.tab
18Nov2010   M_01_006.raw    M006.pro          M006.tab
18Nov2010   M_01_006.raw    M007.pro          M007.tab
18Nov2010   M_01_008.raw    M008.pro          M008.tab
18Nov2010 - modified M_01_009 to eliminate 2nd header that was present becuase program had to be restarted during net 8 open.
18Nov2010   M_1_009.raw     M009.pro          M009.tab
18Nov2010 - modified M_01_012 by modifying the "#increment_net" indicator so that it would be ignored since a delayed net response took place after it was issued for end of net 8. 
18Nov2010   M_1_012.raw     M012.pro          M012.tabto be restarted during net 8 open.


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Parameters

ParameterDescriptionUnits
towtow number
lat_startlatitude start of MOCNESS cast, negative = South DD.D
lon_startlongitude start of MOCNESS cast, negative = West DDD.D
depth_wdepth of water, seafloor depth from the shipboard 12kHz Knudsen echosounder; seafloor in eventlog meters
netMOCNESS net number, (0-8)
yrday_localyear day as a decimal, based on Julian calendar, local time YYY.Y
num_obsnumber of observations
vol_filtvolume filtered meters^3
pressdepth of observation or sample psi
temptemperature of water degrees C
potemppotential temperature or theta degrees C
salsalinity calculated from conductivity
sigma_0potential density kg/m^3
angleangle of net frame relative to vertical (0-89 degrees) degrees
hzvelhorizontal net velocity m/min
vtvel_minMinimum vertical net velocity for each net measured during mocness tows. m/min
press_avgaverage pressure for a net sample psi
angle_minMinimum angle of tow body relative to vertical (0-89 degrees), used in BIOMAPER-II and MOCNESS systems. degrees
angle_maxMaximum angle of tow body relative to vertical (0-89 degrees), used in BIOMAPER-II and MOCNESS systems. degrees
angle_avgAngle of tow body relative to vertical (0-89 degrees), used in BIOMAPER-II and MOCNESS systems. Average is the mean of all observations, not just the mean of the global minimum and maximum. decimal degrees
hzvel_minMinimum horizontal net velocity, reported as meters per minute, used in MOCNESS system. m/min
hzvel_maxMaximum horizontal net velocity, reported as meters per minute, used in MOCNESS system. m/min
hzvel_avgAverage horizontal net velocity, reported as meters per minute, used in MOCNESS system. Average is the mean of all observations, not just the mean of the global minimum and maximum. m/min
potemp_minMinimum potential temperature (International Practical Temperature Scale - 68 ,or 90. When known, the scale will be reported in the units field of the documentation file. degrees Celsius
potemp_maxMaximum potential temperature (International Practical Temperature Scale - 68 ,or 90. When known, the scale will be reported in the units field of the documentation file. degrees Celsius
potemp_avgAverage potential temperature (International Practical Temperature Scale - 68 ,or 90. When known, the scale will be reported in the units field of the documentation file. Average is the mean of all observations, not just the mean of the global minimum and maximum. degrees Celsius
press_minMinimum water pressure at measurement; depth reported as pressure; positive number increasing with water depth. psi
press_maxMaximum water pressure at measurement; depth reported as pressure; positive number increasing with water depth. psi
sal_minMinimum salinity calculated from conductivity. dimmensionless
sal_maxMaximum salinity calculated from conductivity. dimmensionless
sal_avgAverage salinity calculated from conductivity. Average is the mean of all observations, not just the mean of the global minimum and maximum. dimmensionless
sigma_0_minMinimum potential density. kilograms/meter^3
sigma_0_maxMaximum postential density. kilograms/meter^3
sigma_0_avgAverage potential density. Average is the mean of all observations, not just the mean of the global minimum and maximum. kilograms/meter^3
vtvel_maxMaximum vertical net velocity for each net measured during mocness tows. m/min
vtvel_avgAverage vertical net velocity for each net measured during mocness tows. Average is the mean of all observations, not just the mean of the global minimum and maximum. m/min
temp_minMinimum water temperature for each net measured during mocness tows. degrees Celsius
temp_maxMaximum water temperature for each net measured during mocness tows. degrees Celsius
temp_avgAverage water temperature for each net measured during mocness tows. Average is the mean of all observations, not just the mean of the global minimum and maximum. degrees Celsius
cruiseidCruise identifier (e.g. EN484 = R/V Endeavor cruise 484). unitless


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Instruments

Dataset-specific Instrument Name
MOCNESS1
Generic Instrument Name
MOCNESS1
Generic Instrument Description
The Multiple Opening/Closing Net and Environmental Sensing System or MOCNESS is a family of net systems based on the Tucker Trawl principle. The MOCNESS-1 carries nine 1-m2 nets usually of 335 micrometer mesh and is intended for use with the macrozooplankton. All nets are black to reduce contrast with the background. A motor/toggle release assembly is mounted on the top portion of the frame and stainless steel cables with swaged fittings are used to attach the net bar to the toggle release. A stepping motor in a pressure compensated case filled with oil turns the escapement crankshaft of the toggle release which sequentially releases the nets to an open then closed position on command from the surface. -- from the MOCNESS Operations Manual (1999 + 2003).


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Deployments

EN484

Website
Platform
R/V Endeavor
Report
Start Date
2010-09-22
End Date
2010-09-30
Description
Cruise EN484, Chief Scientist Gareth Lawson's September 2010 Krill cruise to the northern flank of Georges Bank and the southern portion of the Gulf of Maine region (42 North 67.5 West), is the first of two cruises in Fall 2010 doing the same work in the same study location. The cruise was scheduled to allow an examination of the impact of herring predation on euphausiid aggregations. The first cruise each year (two similar cruises are planned for 2011) is timed to begin one week after the NOAA Ship Delaware II will have commenced its herring survey. Real-time data collected during that survey will be used to define the exact survey grid for our project. During EN484, the first 2010 cruise, the herring were expected to be pre-spawning and therefore not feeding on euphausiids (the target species for this project). The second cruise each year is timed to begin in the last week of October (EN487 in 2010). At this time, herring and euphausiids will still be present in the study region, but the herring will be post-spawning and will have resumed feeding on euphausiids. Cruise information and original data are available from the NSF R2R data catalog.

Processing Description
 See Dataset Description - Processing for notes.

EN487

Website
Platform
R/V Endeavor
Report
Start Date
2010-10-27
End Date
2010-11-06
Description
Cruise EN487, Chief Scientist Gareth Lawson's October-November 2010 Krill cruise to the northern flank of Georges Bank and the southern portion of the Gulf of Maine region (42 North 67.5 West), is the second of two cruises completed for the Gulf of Maine Krill project in Fall 2010.  The cruises were designed to conduct the same work in the same study location. The timing of the cruises was selected to allow an examination of the impact of herring predation on euphausiid aggregations. The first cruise (cruise EN484 in 2010) each year (two similar cruises are planned for 2011) is timed to begin one week after the NOAA Ship Delaware II will have commenced its herring survey. Real-time data collected during that survey will be used to define the exact survey grid for our project. During the first cruise, EN484, the herring were expected to be pre-spawning and therefore not feeding on euphausiids (the target species for this project). The second cruise each year (EN487 in 2010) is timed to begin in the last week of October. At this time, herring and euphausiids will still be present in the study region, but the herring will be post-spawning and will have resumed feeding on euphausiids. EN487 cruise track JPEG image from URI (vessel operator) Cruise information and original data are available from the NSF R2R data catalog.

CT2010

Website
Platform
R/V Connecticut
Start Date
2010-07-08
End Date
2010-07-16
Description
The CT2010 cruise was supported by funds from Woods Hole Sea Grant, and field work was done on the southern New England Shelf and in nearby slope waters.  This is a different study area from the sites visited by the other Krill project cruises that sampled in the Gulf of Maine.


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Project Information

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)

Coverage: Gulf of Maine; Georges Bank


from the NSF award abstract:

Distribution, Aggregation, and Ecological Importance of Euphausids in the Gulf of Maine Region

Zooplankton are key members of marine ecosystems, but the biological and physical factors governing their distribution and aggregation are not fully understood, especially at the continental shelf break and margins of the deep basins of the shelf. Euphausiids are an important group of crustacean zooplankton in North Atlantic pelagic food webs and represent an interesting model species for the study of zooplankton aggregation due to their strong swimming capabilities and active aggregative behaviors. This project will address the hypotheses that the formation and variability of euphausiid aggregations along the northern flank of Georges Bank and the southern portion of the Gulf of Maine during fall relate to the interaction of physical concentration mechanisms with local topography and with plasticity in diel vertical migration and active aggregative behaviors, and that this plasticity arises from variability in food availability and predation by herring. These hypotheses will be addressed through a field program employing a comprehensive array of sensors, including both conventional narrowband and recently-developed broadband acoustic systems to sample the euphausiids, and a variety of other acoustic, optical, net, and other sampling devices to quantify their physical and biological environment. These sensors will be used in an inventive combination of (1) coarse-scale grid surveys to characterize along- and across-slope variability in the distribution of euphausiids, their predators, other zooplankton, phytoplankton, and physical conditions (e.g., the flow field), and (2) fine-scale adaptive surveys used to track individual euphausiid aggregations and observe how their three-dimensional structure and vertical position vary with changing environmental conditions. Repeat surveys will be timed to capitalize on known or likely variations in the flow field, food availability, light levels, and predation.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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