Shelfbreak frontal dynamics

Ship

RV Neil Armstrong

Vehicles

Cruise Party

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

Christian Petitpas: Principal Investigator
UMass Dartmouth USA
+1 508 999 8953
cjadlowic@umassd.edu

Walker Smith: Principal Investigator
Virginia Institute of Marine Science USA
+1 804 684 7709
wos@vims.edu

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

Rachel Stanley: Principal Investigator
Wellesley College USA
+1 781 283 3122
rachel.stanley@wellesley.edu

Jefferson Turner: Principal Investigator
UMass Dartmouth USA
+1 508 999 8229
jturner@umassd.edu

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

Departure: WHOI on Apr 18, 2018

Arrival: WHOI on May 1, 2018

Mobilization Date: Apr 16, 2018

Demobilization Date: May 2, 2018

Supporting documentation:

»station_coordinates.txt

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.

Pre-cruise planning meeting: Visit WHOI

Media personnel on board: Video
Dan Brinkhaus (ScienceMedia) will film a documentary.

Stations:

Funding Agency: NSF #1657803

- added NSF #1657803 on Nov 8, 2017 8:07 AM by
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R/V Armstrong

Shipboard Equipment

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


Shipboard Equipment Notes:

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?


Shipboard Communication Notes:

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
Precipitation
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

GPS

Navigation Notes:

Winches

UNOLS Winch Pool

Winch Notes:

Wire use and application

CTD Winch with .322" Electro-mechanical wire


Wire Notes:

Slip ring required? no	Number of conductors:
Non-standard wire required? no	Type:
Traction winch required? no	Describe:

Portable Vans

Isotope Van

Other Science Vans:

Over the Side Equipment

Will you be bringing any equipment (winches, blocks, etc.) that lowers instruments over the side? yes

Details: VPR winch

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

Radioactive Material

Radioiosotopes: yes

Additional Information

Is night time work anticipated on this cruise? yes

Specialized tech support (Seabeam, coring, other): 

Other required equipment and special needs: 
Date Submitted: Nov 8, 2017 3:59 PM