Woods Hole Oceanographic Institution

Cruise Planning Synopsis

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AR29: McGillicuddy (SBF)


RV Neil Armstrong

Cruise Party

Dennis McGillicuddy: Principal Investigator, Chief Scientist
Woods Hole Oceanographic Institution Bigelow 209A, MS#11 Woods Hole, Ma. USA 02543
+1 508 289 2683

Christian Petitpas: Principal Investigator
UMass Dartmouth USA
+1 508 999 8953

Walker Smith: Principal Investigator
Virginia Institute of Marine Science USA
+1 804 684 7709

Heidi M. Sosik: Principal Investigator
Woods Hole Oceanographic Institution Redfield 3-16, MS#32 Woods Hole, Ma. USA 02543
+1 508 289 2311

Rachel Stanley: Principal Investigator
Wellesley College USA
+1 781 283 3122

Jefferson Turner: Principal Investigator
UMass Dartmouth USA
+1 508 999 8229

Weifeng Zhang: Principal Investigator
Woods Hole Oceanographic Institution Bigelow 201, MS#11 Woods Hole, Ma. USA 02543
+1 508 289 2521

Departure: Apr 17, 2018


Arrival: Apr 30, 2018


Operations Area

OOI Pioneer Array
Lat/Lon: 40° 0.0′ N / 71° 0.0′ W
Depth Range: 60 / 2500
Will the vessel be operating within 200 NM of a foreign country? no

Science Objectives

The continental shelfbreak of the Middle Atlantic Bight supports a productive and diverse ecosystem. Current paradigms suggest that this productivity is driven by several upwelling mechanisms at the shelfbreak front. This upwelling supplies nutrients that stimulate primary production by phytoplankton, which in turn leads to enhanced production at higher trophic levels. Although local enhancement of phytoplankton biomass has been observed in some synoptic measurements, such a feature is curiously absent from time-averaged measurements, both remotely sensed and in situ. Why would there not be a mean enhancement in phytoplankton biomass as a result of the upwelling? One hypothesis is that grazing by zooplankton prevents accumulation of biomass on seasonal and longer time scales, transferring the excess production to higher trophic levels and thereby contributing to the overall productivity of the ecosystem. However, another possibility is that the net impact of these highly intermittent processes is not adequately represented in long-term means of the observations, because of the relatively low resolution of the in situ data and the fact that the frontal enhancement can take place below the depth observable by satellite.

Science Activities

We will obtain cross-shelf sections of physical, chemical, and biological properties within the Pioneer Array. Nutrient distributions will be assayed together with hydrography to detect the signature of frontal upwelling and associated nutrient supply. We expect that enhanced nutrient supply will lead to changes in the phytoplankton assemblage, which will be quantified with conventional flow cytometry, imaging flow cytometry (Imaging FlowCytobot, IFCB), in situ optical imaging (Video Plankton Recorder, VPR), traditional microscopic methods, and HPLC pigments. Zooplankton will be measured in size classes ranging from micro- to mesozooplankton with the IFCB and VPR, respectively, and also with microscopic analysis. Biological responses to upwelling will be assessed by measuring rates of primary productivity, zooplankton grazing, and net community production. These observations will be synthesized in the context of a coupled physical-biological model to test the two hypotheses that can potentially explain prior observations: (1) grazer-mediated control and (2) undersampling. Hindcast simulations will also be used to diagnose the relative importance of the various mechanisms of upwelling.

Additional Info

Pre-cruise Planning Meeting: Visit WHOI
Media personnel on board: Video
Dan Brinkhaus (ScienceMedia) will film a documentary.


Supporting documentation:



Funding Agency: NSF
Grant or contract number: 1657803

Scientific Instrumentation for R/V Armstrong

Shipboard Equipment

Bathymetry System 12 kHz
ADCP 300 kHz
ADCP 150 kHz
Deionized Water System
Science Underway Seawater System
Fume Hood
EK80 Sonar
Dynamic Positioning System
Incubation Area
ADCP 38 kHz

Shipboard Communication

Basic Internet access via HiSeasNet
Is there a need to receive data from shore on a regular basis?
Is there a need to transfer data to shore on a regular basis?

CTD/Water Sampling

Wet Labs ECO-AFL fluorometer
Wet Labs C*Star transmissometer (660nm wavelength)
Seapoint STM turbidity sensor
SBE43 oxygen sensor
911+ Rosette 24-position, 10-liter bottle Rosette with dual T/C sensors
Biospherical underwater PAR (1000m depth limit) with reference Surface PAR
Wet Labs FLNTURTD Combination Flourometer and Turbidity Sensor

Critical CTD Sensors

MET Sensors

Barometric Pressure
Air temperature
Relative Humidity
Wind speed and direction
Short Wave Solar Radiation
Long Wave Solar Radiation

Sample Storage

Freezer -70°C 25 cu. ft.
Freezer -70°C 3.2 cu. ft. ea.
Storage Notes:


Navigation Notes:


UNOLS Winch Pool
Winch Notes:

Wire use and application

CTD Winch with .322" Electro-mechanical wire
Winch Notes:

Standard Oceanographic Cables

Slip ring required? no
Non-standard wire required? no
Traction winch required? no

Portable Vans

Isotope Van

Special Requirements

Elecrical Power: no Identify 
Equipment Handling: no Identify: 
Inter/intraship Communications: no Identify: 
Science Stowage: no Identify: 
Water: no Identify: 

Additional Cruise Items/Activities

Explosive Devices:no
Portable Air Compressors:no
Flammable Gases:no
Small Boat Operations:no
SCUBA Diving Operations:no

Hazardous Material

Will hazardous material be utilized?yes
Describe deployment method and quantity:

Radioactive Material


Additional Information

Is night time work anticipated on this cruise?yes
Specialized tech support (Seabeam, coring, other):
Other required equipment and special needs:

Checklist & Notes


U.S. Customs Form: no
Diplomatic Clearance: no
Date Submitted:
Date Approved:
Agent Information:
Isotope Use Approval: no
Isotope Notes:
SCUBA Diving: no


SSSG Tech: