Cruise Planning Questionnaire

    Vehicle(s) required:
    Name of ship for ROV ops:
    Ch Sci:
Andreas Thurnherr
Lamont-Doherty Earth Observatory
61 Route 9W
Palisades, NY 10964
(845) 365-8816
    POC / contact info:
Departure port & date:San Diego, CA; October 24, 2006
    Distance to first station:
    Number of stations:
    Distance between stations:
    Total days on station:
Arrival port & date:Manzanillo, Mexico; November 17, 2006
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:
Other Specify:Austrian Science Foundation

Grant or contract number: OCE 04-25361

    Science objectives/activities planned:
This is the first of three cruises of the LADDER project, which aims to address the following questions (see 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?

In order to address these questions, an observational program will be carried out on the crest of the East Pacific Rise near 9:50N. The main activities are:

1) Vertical distributions of larval invertebrates. We will position plankton pumps and sediment traps near bottom and at the height of the neutrally buoyant plume to collect larvae and determine where species reside during different stages of heir larval life spans.

2) Lateral distributions of larvae. We will 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, using sediment traps positioned along the ridge axis and plankton pumps positioned within and outside the ASCT.

3) Temporal variation of larval abundance. The short term sediment trap samples (recovered in June and October 2006) and long-term samples (recovered after ~1 year in 2007) will be used to determine how variations in larval abundance compare to changes in local and regional hydrodynamics (e.g., changes in the direction of mean flow, passage of mesoscale eddies, etc).

4) Colonization and larval supply. Colonization experiments will be conducted in conjunction with time-series sampling of larvae in the traps in order to quantify the influence of larval supply on recruitment, and monitor changes in recruitment as the new vent communities mature. Our main focus will be on the diffuse-flow communities, but see also colonization project (PI: Pradillon) described below.

5) Characterization of established and new vent communities via video imagery. This objective is part of a larger project (PIs Beaulieu and Rhzanov) described below.

6) Tracer Release. Three kilograms of sulfur hexafluoride will be released from Alvin with a special tracer release system in a study of dispersion of vent larvae. The aim is to release this tracer within the axial depression at the crest of the ridge of the East Pacific Rise near 9:40N. The tracer will be used to track water and suspended particles from the site of the release over a period of about 40 days. The distribution of the tracer will be measured on a subsequent Atlantis cruise in December 06/January 07 with CTD/rosette casts.

7) Mooring Array. Seven moorings equipped with 15 current meters, 2 velocity profilers and 3 sediment traps will be deployed in a cross-shaped array centered on the EPR crest at 9:30N. Three axial moorings will be deployed precisely within the axial trough between 9:10 and 9:0N; a cross-axial mooring line will be deployed at 9:30N between 103:55 and 104:35W. The moorings will collect data between 2000 and 2900m. Recovery is planned after ~1year in fall 2007.

8) Bottom-mounted ADCP. At the tracer-release site a bottom-mounted ADCP will be deployed. Recovery is planned at the end of the tracer-sampling cruise in January 2007.

9) CTD/LADCP and microstructure surveys. An extensive survey will be carried out at night both along the EPR axis and on the flanks.

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.

DEVELOPMENT, GROWTH AND CELL KINETIC STUDIES IN RIFTIA PACHYPTILA (PI: Bright): The aim of this project is to study the infection process, growth, and developmental processes in Riftia pachyptila symbiosis as well as cell kinetics in symbiont-containing and symbiont-free host tissue. Cruise activities include recovery and re-deployment of tubeworm settlement devices, and recovery of basalt from warm vents to collect small tubeworms.

PROKARYOTIC AND VIRAL COMMUNITIES (PI: Williamson): The aim of this project is to estimate abundances, carry out prophage induction experiments and metagenomic analysis of prokaryotic and viral communities in water samples from hydrothermal vents and in off-axis non-vent water. The main cruise activity will be in-situ filtration of large volumes of water.

EARLY LIFE STAGES OF ALVINELLA POMPEJANA (PI: Pradillon): The goal of this project is to understand how embryos of the polychaete annelid Alvinella Pompejana are able to disperse and colonize new vent sites. Two main activities will be carried out during the cruise: 1) In situ experiments will be carried out at vent sites to analyze early development and larval colonization in relation to local environmental conditions. 2) In vitro development experiments will be conducted on board to analyze sensitivity of early embryos at different pressure levels.

PHOTOGRAPHIC DIVE TRACKS (PIs: Beaulieu & Rhzanov): The goal of this project is to develop software for creating geo-referenced video mosaics using Alvin navigation and image data. This cruise will serve as a test bed for the software, which will be run overnight so that a "photographic dive track" is available the next day for dive reports and subsequent dive planning.

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

Is nighttime work anticipated on this cruise? Yes

    Critical MET sensors:
    Critical CTD sensors:
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: 8 (max. possible)
Ultra-short baseline (USBL) navigation? Yes
Doppler/GPS navigation? Yes

Will you be using portable science vans? How many: tbd; contact Scott Worrilow for CM van requirements; contact Jim Ledwell for tracer van requirements

Science Van #1
Science Van #2
Science Van #3

Anticipated standard oceanographic cable use:

Instrument Weight(s)
Maximum Depth
    Conducting hydro
CTD (with rosette & LADCP system)
not known
    Steel hydro
    Steel trawl
    .681" fiber optic
    Do you require slip rings?
YesNumber of conductors:sufficient for CTD
    Do you need non-standard wire?
NoIf so, what type?
    Do you need a traction winch?
Will you be bringing any equipment (winches, blocks, etc.) that lowers equipment over the side? Yes

If yes, please provide details: There is going to be a winch on board for a previous cruise that Scott Worrilow will be using for mooring deployments. Standard TSE mooring winch to be supplied by the WHOI rigging shop.
Will there be special requirements for:

    Electrical power
    Equipment handling
    Inter/intraship communications
    Science stowage

If yes to any of the above, please identify: please contact PI for details

Will any of the following items be used on board?

    Explosive devices
    Portable air compressors
    Flammable gases
    Isotope van

Will hazardous material be used aboard, or deployed by an ROV? Yes

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?
A variety of hazardous substances will be used by Mullineaux, Ledwell, Bright and Williamson. Some of Worrilow's instruments use Lithium batteries.