Cruise Planning Questionnaire


Ship: ATLANTIS
    Vehicle(s) required:
ALVIN
    Name of ship for ROV ops:
    Ch Sci:
Lauren Mullineaux
    Affiliation:
WHOI
    Address:
MS 34
Woods Hole Oceanographic Institution
Woods Hole MA 02543
    Phone:
508 289-2898
    Email:
lmullineaux@whoi.edu
    POC / contact info:
Departure port & date:Manzanillo
    Distance to first station:
    Number of stations:
    Distance between stations:
    Total days on station:
Arrival port & date:Manzanillo
Op area:EPR 9:50N (Ridge2000 EPR ISS site)
Lat/Lon:104:15W, 9-10N
Depth range:2500-3000m
    Will the vessel be operating within 200 NM of a foreign country?
    Which country?
    Are visas or special travel documents required?

Funding agency:
      NSF
Specify:

Grant or contract number:

    Science objectives/activities planned:
This is the third of three cruises of the LADDER project, which aims to address the following questions (see http://www.ldeo.columbia.edu/~ant/LADDER for details):

Bio-1) What are the influences of advection and eddy diffusion on the maximal dispersal distance of vent species with given larval life spans?

Bio-2) What are the effects of ontogenetic changes in larval behavior (i.e., vertical positioning) on species' dispersal distances?

Bio-3) How are the probabilities that larvae will be lost from the ridge system influenced by topography and flow? Might the axial summit trough inhibit off-axis transport of larvae, and serve as a conduit between habitable vent sites?

PO-1) What are the mean and temporally varying flows in the vicinity of a mid-ocean ridge crest, and what is their spatial structure and coherence?

PO-2) What is the magnitude of the diapycnal diffusivity near the ridge crest?

PO-3) How rapid is lateral dispersion, and how effective is lateral homogenization by eddy diffusion near the ridge crest?

An observational program will be carried out on the crest of the East Pacific Rise near 9:50N. The main activities are:

1) Recovery of Mooring Array. Seven moorings equipped with 15 current meters, 2 velocity profilers and 3 sediment traps will be recovered from a cross-shaped array centered on the EPR crest at 9:30N. Three axial moorings were positioned within the axial trough between 9:10 and 9:50N; a cross-axial mooring line was deployed at 9:30N between 103:55 and 104:35W. The moorings collected data between 2000 and 2900m.

2) CTD/LADCP profiling. An extensive survey will be carried out at night, and occasionally during daytime, both along the EPR axis and on the flanks.

3) Microstructure profiling. A survey using a deep microstructure profiling system (DMP) will be coordinated with the CTD/LADCP deployments, to be carried out at night, and occasionally during daytime, along the EPR axis and on the flanks.

4) Recover larval sediment trap moorings. Two short moorings with sediment traps will be recovered from a site near 9-50 (TrapL1, S of Ty/Io vent, near NA) and near 9-30 (TrapL2, near CA). These were used to monitor temporal variation in larval supply to the vent sites.

5) Deploy and recover plankton-pump moorings. Pairs of moorings will be deployed along the ridge axis, with one near and the other away from an active vent community. Each mooring will support two plankton pumps, one near-bottom (4 mab) and the other at the level of the neutrally-buoyant plume. Four sets of pairs will be deployed over the course of the cruise, each for a ~2-day interval. The samples will be used to quantify larval abundances with respect to potential barriers to dispersal (e.g., the axial summit trough walls, or lateral offsets in the ASCT) and distance from potential source populations.

6) Monitor colonization on the seafloor. Colonization experiments will be conducted with basalt blocks and plastic sandwiches placed on the seafloor at active vent sites. We will recover experiments from Dec. 2006 and set out new ones. Our main focus will be on the diffuse-flow communities.

7) Characterization of established and new vent communities via video imagery. This is a continuation of the Beaulieu and Rhzanov project.

In addition to LADDER, time will be devoted to the following projects:

Hydrothermal vent meiobenthos (PI: Bright): The aim of this project is to study the present status of the meiobenthic community shortly past eruption and to follow the succession of colonization and development of communities. Cruise activities include collection of meiofauna from different natural substrates, from the water column at various heights above the bottom, and from off-axis sediments. Additionally, meiofauna settlement devices will be deployed and recovered.

Geochemistry of hydrothermal particulates (PI: Breier): collection of 36 samples of particles in a system during 4-5 hours of wire-time as part of a CTD-rosette cast.

Water column denitrification (PI: Schwartz) Collection of water column samples for analysis of N2/Ar ratios and dissolved nutrients to assess water column denitrification rates in the study region. Analysis of water samples from the vent field to provide an interesting assessment of the relative influence of N cycling in these regions versus the overlying water column.

WHOI shipboard scientific instrumentation desired:
    12 kHz transducer
Fume hood
    Relay transponder for wire use
Refrigerator
Deionized water system
CTD/rosette system-70 deg freezer
SalinometerWalk-in cooler (AT only)
Pinger for wire use

Is nighttime work anticipated on this cruise? Yes

    Critical MET sensors:
    Critical CTD sensors:
CTD/Rosette -23 X10L - all standard CTD sensors, light-scattering sensor, LADCP

Do you need Seabeam? (AT and KN only) No

Long baseline (LBL) transponder navigation? Yes No. of xpndrs/nets:
Ultra-short baseline (USBL) navigation? Yes
Doppler/GPS navigation? Yes

Will you be using portable science vans? No How many:


Science Van #1
Science Van #2
Science Van #3
    Type/size
    Location
    Water
    Power

Anticipated standard oceanographic cable use:

Instruments(s)
Instrument Weight(s)
Maximum Depth
    Conducting hydro
    Steel hydro
    Steel trawl
    .681" fiber optic
    Do you require slip rings?
Number of conductors:
    Do you need non-standard wire?
If so, what type?
    Do you need a traction winch?
Will you be bringing any equipment (winches, blocks, etc.) that lowers equipment over the side? No

If yes, please provide details:
Will there be special requirements for:

    Electrical power
    Equipment handling
Yes
    Inter/intraship communications
    Science stowage
Yes

If yes to any of the above, please identify:

Will any of the following items be used on board?

    Explosive devices
No
    Portable air compressors
No
    Flammable gases
No
    Radioisotopes
No
    Isotope van
No

Will hazardous material be used aboard, or deployed by an ROV? No

What measures or plans have been made a) in the event of a spill, and b) for the removal and/or disposal of these materials at the completion of the cruise?
We request to leave batteries and hazardous material onboard until Atlantis returns to a US port