Easter Microplate Expedition 2005


This expedition has been made possible by National Science Foundation grants to Dr. Robert Vrijenhoek (NSF OCE-0241613) and Dr. Cindy Van Dover (NSF OCE-0350554)

Ship & Vehicle: atlantislarge.jpg (44820 bytes)

  • RV Atlantis
    RV Atlantis is operated by the Woods Hole Oceanographic Institution (WHOI).  For more information please visit WHOI's Atlantis website.

  • DSV Alvinalvin.jpg (51906 bytes)
    The deep submergence vehicle (DSV) Alvin,  operated by the Woods Hole Oceanographic Institution (WHOI), is the submersible that carries three people (a pilot and two observers) down to the seafloor. A titanium sphere (inside the  white fiberglass hull at the bow, which is to the left in the image) protects the people from the tremendous pressure in the deep sea. Video and still images are taken, and samples are collected with a manipulator arm and the tools below. 

    For more information about this vehicle visit WHOI's Alvin website.


  • Suction samplerT425_SuctionBiojar.png (605208 bytes)
    A clam has just been vacuumed into the suction tube (top). The system shown is on MBARI's ROV Tiburon. On the DSV Alvin, there is a carousel out of view of the observers with mesh-lined canisters for holding the specimens and volcanic glass sucked up by the sampler

  • Wax-tipped samplerwax-corer2.jpg (121818 bytes)
    This device is used to collect volcanic glass fragments from the surface of a flow. It is held by the manipulator arm, which presses it on the rock with a stamping action. Fragments that break off on impact are trapped in the wax on the tip, which is melted in the lab to liberate the particles for analysis.

  • Sediment scoopsT322_scoopBag.png (683233 bytes)
    These canvas bags, with T-handles the vehicle's manipulator arm can hold, are used for collecting mud, sand, gravel or unattached animals.

  • Multibeam sonar
    The Seabeam 2100/12 multibeam sonar system mounted on the hull of the R/V Atlantis will be used to map the seafloor. We will "mow the lawn" over the dive site before a dive, mapping an approximately 10 km wide swath of the seafloor at each pass, to improve our chances of finding the ridge axis and hydrothermal vents during the dive. For more information visit WHOI's multibeam sonar site

  • Dredgedredge_640.JPG (63383 bytes)
    Shown here lashed on deck, the rock dredge is a metal frame several feet across with a chain mesh "bag" attached. It is dragged on the bottom behind the ship to collect rock samples. A dredge gets much more material but with less precise locations for the samples than from a submersible.

  • Mussel potmussel_pots_crop.jpg (85026 bytes)
    The mussel pot is deployed by the Alvin for Cindy Van Dover's community structure studies. The pot is an inverted stainless steel stew pot with a kevlar bag attached inside. A "T" handle on top is being held by the manipulator arm (the claw is in view in photo's upper center). Turning the manipulator while it is clamped on the "T" handle cinches up the kevlar bag inside. The bag encloses the mussels and accompanying organisms that live in the mussel bed for secure transport to the surface.

  • MagnetometerMagnetometer2_640.JPG (68353 bytes)
    Sensor to detect variations in the Earth's magnetic field.  As the magnetometer is towed behind the ship, it will record the subtle variations in the magnetic field that are in part related to the magnetic field associated with the underlying oceanic crust. As seafloor is generated at mid-ocean spreading centers, magnetic minerals in the melt align with the direction of the Earth's magnetic field at the time and then chill, preserving that polarity. However the Earth's magnetic field is not constant. The magnetic field of the Earth has reversed many times over geologic history (at times a compass needle would have pointed toward geographic South). Thus, maps of the magnetic field over  seafloor formed  during alternating normal and reversed magnetic conditions have a striped  magnetic signature. The accumulation of this kind of data allows geophysicists to estimate the age of the crust, see how tectonic plates have rotated, and locate active and relict spreading ridges.

  • Temperature probeTempProbe_640.JPG (42025 bytes)
    To measure the temperature of vent fluids. The sensor is the long wire on the right. The Alvin carries two: one optimized for low temperatures and one for high.

  • Crab trapCrabTrap_640.jpg (55733 bytes)
    Baited with leftovers from the galley, crab traps are deployed overnight to capture crabs and other scavengers.

  • Niskins_640.JPG (71579 bytes)Niskin bottles
    To collect water samples as well as the tiny bacteria and plankton in that volume. The caps at both ends are open until the bottles are tripped, when the caps snap closed. The Alvin carries a rack of five 1.5 liter bottles.