Woods Hole Oceanographic Institution

Cruise Planning Synopsis

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AT42-15: Ohman "CCE-LTER3"


R/V Atlantis

Cruise Party

Mark Ohman: Chief Scientist, Principal Investigator
La Jolla, California USA 92093-0218
+1 858 534 2754

Departure: Aug 5, 2019

San Diego

Arrival: Sep 6, 2019

San Diego

Operations Area

Northeast Pacific, west of Pt. Conception
Lat/Lon: 35° 0.0′ N / 122° 0.0′ W
Depth Range: 0 / 3000
Will the vessel be operating within 200 NM of a foreign country? N/A
Are visas or special travel documents required? no

Science Objectives

Our objectives are to understand and quantify key mechanisms that transport coastal production and populations offshore in the CCE region, including the magnitudes and length scales of transport and their climate sensitivities.  The principal hypotheses we seek to test are:

H1: Lateral transport dominated by the interaction of Ekman transport and westward propagating coastal filaments provides a significant flux of nutrients and organisms to offshore waters.

H2: Carbon export associated with offshore transport is determined by in situ evolution of communities and nutrient regimes, and by subduction occurring largely at sharp frontal density gradients. 

The processes measured on this cruise will include primary and secondary production, net community production, carbonate system variables, grazing by microzooplankton and mesozooplankton, dissolved iron and ligand effects on phytoplankton growth, carbon and nitrogen cycling, and export of carbon and other elements in both particulate and dissolved forms.  The pelagic food web will be characterized, extending from viruses, prokaryotic and eukaryotic microbes, micro- and meso-zooplankton, to nektonic organisms (the latter as acoustic backscatter) using state-of-the-art measurement methods. 

Most measurements will be made in a Lagrangian reference frame while following discrete water parcels for 3-5 days at a time.  These water parcels will be selected to represent different stages in the temporal evolution of a coastal filament: i.e., nearshore near the upwelling source and presumed origin of the filament; somewhat further offshore, along the axis of the filament, as upwelled waters and entrained communities are advected offshore; and still further offshore, near the terminus of a filament, where export fluxes are expected to be elevated.  Our analyses will extend from the ocean surface through the euphotic zone, and in some locations into the mesopelagic ocean to 1000 m or deeper.  We also expect to conduct a brief Benthic Boundary Layer (BBL) study to understand the relationship between coastal iron supply in nearshore sediments and the flux of iron into the coastal ocean via coastal filaments. 

Our Broader Impacts activities will include seagoing research opportunities and training for multiple graduate students, undergraduate students and other volunteers, as well as regular communication with the general public via an online blog created by a graduate student. 

Science Activities

Our basic cruise design is Lagrangian, i.e., we will be following individual water parcels rather than sampling on a fixed grid of stations.  Each water parcel is selected based on real-time satellite imagery and in situ surveys (usually with a Moving Vessel Profiler).  Once an appropriate water parcel is identified, a satellite-tracked sediment trap array is released and used to follow the parcel and associated plankton populations for 3-5 days at a time while we make a series of other measurements.  Such measurements include CTD-rosette profiles, in situ imaging with an UVP5 plankton camera, seawater collections for in situ drifting incubations for growth and grazing experiments, shipboard deck incubations, Trace Metal CTD and Go-Flo casts for studies of iron limiation, zooplankton bongo net tows, MOCNESS vertically stratified net tows, live zooplankton collections for copepod egg production experiments, and other activities.

Vertical export of carbon and other elements will be determined by drifting sediment traps and a geochemical method that measures Th:Ur disequilibrium.

Continuous underway measurements will be made of O2:Ar ratios using a flow through mass spectrometer, CO2:pH using a custom carbonate system device, multi-spectral fluorescence using an Advanced Laser Fluorometer, multi-frequency acoustic backscatter using a Simrad (Kongsberg) EK-60, as well as standard flow-through measurements of T,S,O2, Chl-a fluorescence, Doppler currents, etc.   

A towed SeaSoar will be used to make larger-scale surveys of our study region toward the beginning and end of the cruise.  A free-fall Moving Vessel Profiler (MVP) with computer-controlled winch will conduct local site surveys and analyze small-scale spatial gradient repeatedly throughout the cruise.

Cross-frontal transects will be carried out that sample the gradient regions associated with coastal upwelling filaments, as well as the properties of the filament cores.

Supporting instruments will include a Spray glider deployed from shore as well as a new Zooglider deployed and recovered from Atlantis.

Additional Info

Pre-cruise Planning Meeting: Teleconference
Meeting Notes: People will be in different time zones so we will need to coordinate carefully.


  Station 1
  Distance: 30
  Days: 0.25
  Latitude: 32° 51.632’ N
  Longitude: 117° 40.146’ W

  Station 2
  Distance: 250
  Days: 30
  Latitude: 35° 0.0’ N
  Longitude: 122° 0.0’ W

Supporting documentation:


Funding Agency: NSF
Grant or contract number: OCE-16-37632

Scientific Instrumentation for R/V Atlantis

Other Science Vans:

Shipboard Equipment

Bathymetry System 12 kHz
Bathymetry System 3.5 kHz
ADCP 75 kHz
Deionized Water System
Science Underway Seawater System
Navigation - Heading
Fume Hood
Navigation - Position

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

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

Critical CTD Sensors

Trace Metal CTD Rosette (user-supplied)

MET Sensors

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

Sample Storage

Climate Controlled Walk-in
Freezer -70°C 25 cu. ft.
Freezer -70°C 3.2 cu. ft. ea.
Refrigerator 8.6 cu. ft.
Storage Notes:
Also Freezer -18 C
At least 2 fume hoods required


Will you be using Long Base Line (LBL) navigation? no
How many nets? null
How many tansponders? null
Will you be using Ultra-short baseline (USBL) navigation?no


Navigation Notes:
Continuous serial NMEA string containing GPS, depth, ship's speed is needed in laboratory for Moving Vessel Profiler computers (1 Hz, 1200 baud).
We will furnish an event log computer (laptop) for the bridge, with a similar (networked) computer for the main lab.


CTD Winch with .322" Electro-mechanical wire
Hydro Winch with .25" hydro wire
Other Portable Winch
Winch Notes:
We need to discuss winch usage with all users.
Desirable, if possible, to have independent winches for:
- CTD-rosette (0.322")
- bongo tows (0.25" hydro)
- Trace Metal-rosette (user-supplied wire and rosette; need winch)
- MOCNESS (0.322" or 0.681" conducting, depending on deployment location)

Wire use and application

Trawl Winch with .681 fiber optic
Hydro Winch with .25" hydro wire
CTD Winch with .322" Electro-mechanical wire
Winch Notes:
Moving Vessel Profiler self-contained winch, fish, and Vectran cable (user-supplied; M. Ohman group).  Weight of fish plus instruments ca. 300 lbs in air; roughly 200 lbs. in water.  Deployed directly aft, winch bolted to deck on one side of A-frame.
Trace Metal sampling requires portable winch that will not contaminate coated wire for iron sampling (K. Barbeau group).  Clean level wind needed.  Non-metallic or clean stainless steel roller, no grease.  Prefer deployed off starboard side.  User will supply cable, block, rosette, water bottles.  Trace Metal rosette to be located with clear access to trace metal clean van.  Rosette weighs 500-600 lbs in air when fully loaded;  weight in water not known.
SeaSoar tow-yowed ca. 300 m to surface.  Multiple sensors (user-supplied) on fish. Standalone winch.  Carl Mattson (SIO ET) will be in charge of this instrument.
Sediment trap array with surface float and satellite transmitter, holey sock drogue, and multiple sediment traps at depths from ca. 75 to 400 m.  Ca. 100 lbs. in water.  Upon recovery grappled, then recovered via A-frame.
Driftarray for grazing studies, with surface float and satellite transmitter, holey sock drogue, and multiple attachment points for bottles in mesh bags at depths between 10-100 m.  < 75 lbs in water.  Upon recovery grappled, then recovered by hand over the rail. 
Zooglider (modifed Spray glider) to be deployed from crane, then either recovered by crane or from small boat.  Weighs ca. 130 lbs in air, essentially neutrally buoyant in water.

Standard Oceanographic Cables

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

Portable Vans

Isotope Van
Science Van 1
Type/size: 20 foot Trace Metal (Moffett) Location: main deck, not far from Trace Metal rosette
Water: no supply; seawater drain hose desirable Power:3 phase, 480 V
Science Van 2
Type/size: 20 foot Isotope van w/ scintillation counter Location: main deck
Water: yes Power:yes

Specialized Deck Equipment

Mooring Deployment/Recovery Equipment Required: no Type: 
Cruise Specific Science Winch Required: yes Type: MVP; Trace Metal; SeaSoar
Nets Required: yes Type: 1-m MOCNESS (202-um); bongo

Over the Side Equipment

Will you be bringing any equipment (winches, blocks, etc.) that lowers instruments over the side? yes Details:
EK60 multi-frequency acoustic transducer pod to be deployed via a side pole mount. 
MVP 200 winch (noted above).  Entirely self-contained winch/boom/fish/cable.
Trace Metal block (noted above).  Plan to spool user-supplied (K. Barbeau) wire on available portable winch aboard Atlantis.  User has specific block.
SeaSoar towed instrument with standalone winch.  Carl Mattson (SIO ET) in charge.  Details have been provided to WHOI vessel science coordinator.
Sediment trap array will be deployed and recovered from the A-frame. Details have been provided to WHOI vessel science coordinator.

Special Requirements

Elecrical Power: yes Identify 480 v, 3 phase, 40 amps for MVP winch on main deck aft
Equipment Handling: no Identify: 
Inter/intraship Communications: yes Identify: We will bring an event logger for the bridge and main lab.
Science Stowage: yes Identify: Extensive stowage for equipment, sample containers, etc.
Water: yes Identify: u/w flow through seawater needs to be cleaned before cruise

Additional Cruise Items/Activities

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

Hazardous Material

Will hazardous material be utilized?yesDescribe deployment method and quantity:
We generally store chemicals (ethanol, formalin, others) in an external Hazmat locker provided by the ship.

Radioactive Material


Additional Information

Is night time work anticipated on this cruise?yesSpecialized tech support (Seabeam, coring, other):
We work 24/7.
Require regular assistance with launch and recovery of MOCNESS, driftarray, CTD-rosette, Trace Metal rosette, zooplankton nets (and other equipment), etc., both night and day.
SeaSoar - Carl Mattson from SIO will be in charge.  He will be accompanied by another technician from SIO.
Other required equipment and special needs:
Reliable internet is mission critical.  Required continuously for real-time tracking of sediment trap and driftarray, near-real-time satellite imagery, glider data, and related data downloads.
CTD-rosette needs acid-cleaned Niskin bottles with Teflon coated springs and silicone 0-rings.  CTD rosette in 24 bottle configuration needs to accommodate user-supplied UVP5 (Underwater Vision Profiler) and ISUS nitrate sensor.  Optional or alternate items requested:  Biospherical Instruments QSP-200L4S underwater PAR sensor, 1000m depth limit with accompanying surface PAR (QSR-240).
Zooglider will be deployed and recovered at sea.  May require use of small boat for recovery.
The ship’s clean seawater flow-through system is essential.  Several user-provided instruments will be connected to it in the ship’s laboratory (including O2:Ar mass spectrometer, pCO2:pH system, Advanced Laser Fluorometer).  Flow through the system needs to be constant at about 5 L/min to ensure a constant system flushing time.  In addition, we require data from a recently calibrated TSG system that monitors T, S, flow rate, Fluorescence and ideally oxygen.  The through piping and traps need to be fully cleaned and flushed prior to the cruise. The fluorometer flow cell needs to be cleaned prior to the cruise and three times during the cruise to avoid the build-up of algae in the flow cell (we will be in productive waters where this can occur within one to two weeks.
Deck incubators will require ample space on the main deck with minimal shadows and running seawater.
MET sensors:

Short Wave Solar Radiation – change to ‘Long and short wave radiation.’  PAR sensor, 2pi

Winch slip rings definitely ARE required.
We request permission to begin installation of MVP winch on 1 or 2 August, prior to other mobilization, if possible.

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: