Monterey Bay Aquarium Research Institute

Mendocino Fracture Zone Cruise - 2001
August 20 - 30, 2001
Over 300 km off the California-Oregon Coast
Logbook

August 21, 2001: Day #2


Here is a thumbnail (click to see a larger image) of Peter Girguis attaching the water sampler to the ROV. The sampler was built by Steve Fitzwater and Luke Coletti. It collects eight 75 ml water samples. Peter is attaching the apparatus to the vehicle before filling it with sterile water (to prevent contamination with surface bacteria).

Jenni Kela writesy: The Western Flyer set sail yesterday August 20, 2001. We departed MBARI and Moss Landing at 1300 local time. The sky has been blue and sunny but the sea rough. After tonight’s upcoming storm the wind is meant to calm down, and we should be able to begin our dive series tomorrow morning, bright and early at 6am. Our first site is along the Mendocino Ridge, just south of the Escanaba Trough. This is the intersection of the Mendocino Fracture Zone and the Gorda spreading ridge (see map posted on August 20th, 2001). The rocks of the Mendocino Fracture Zone are thought to have formed at the Gorda Ridge (both on and off axis) and have since been accreted on to the Pacific Plate.

We have spent much of today preparing for the upcoming seven dives. The science party has organized informal tutorials on how to use different equipment on the ship: VICKI video annotation system (Video Information Capture with Knowledge and Inferencing), the chief scientist camera controls and ArcView navigation program Above you can see Peter Girguis attaching the water sampler onto the ROV Tiburon.

One of our aims on this cruise is to get information about differences in microbial populations present in cracks and fissures on bedrock and overlying sediments in a transform fault environment. In addition to this, water samples directly above the cracks will be collected to analyze the amount and type of microbes in the water to see what the differences are to those in the cracks. On last year’s cruise to the Mendocino Transform Fault a cold seep was found on igneous basement rock. Associated with the seep site were minor amounts of sulfide bearing sediment. This seep site is unique because it is the first found on an active transform fault and related to methane hydrate. We hope to find more seeps, and possible new seeps will take the priority in the microbial population study. However, it is also important to know which microbes and how many live away from seep sites. Sample collection will consist of water samples, sediment push core samples, and grab samples.

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