AT26-24

Ship

Vehicles

Cruise Party

Departure: Nov 30, 2014

Arrival: Dec 12, 2014

Operations Area

Science Objectives

Intellectual Merit: Scientific Motivation and Proposed Program

            Most of the advective heat loss from the oceanic lithosphere occurs on "ridge flanks”, areas far from the magmatic influence of seafloor spreading. Global hydrothermal fluid flows to and from the seafloor on ridge flanks, driven by lithospheric cooling and influenced by basement relief and variations in sediment thickness, are of the same magnitude as the flows from all of Earth's rivers and streams to the oceans. Yet, pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. We have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise, that is hypothesized to discharge 10³–10⁴ L/s of cool (10–20°C) hydrothermal fluid that carries 200-350 MW of lithospheric heat, equivalent to the heat output of a black-smoker vent field.

            We propose to sample this fluid to determine its composition, and to assess the rate of discharge from Dorado outcrop, so that we can quantify the chemical impact of this hydrothermal system. The physical and chemical state of this fluid is typical of fluids that extract heat from the crust and exchange solutes with the overlying ocean across much of the seafloor. Collection of uncontaminated samples from this feature will provide the most accurate estimates of the global impact of ridge-flank hydrothermal circulation. We anticipate that this fluid will be modestly different in composition from bottom seawater, which is why collection of pristine samples is so important, because of the relatively low temperatures of reaction and short residence time of the fluid within basaltic basement. Despite being slightly altered, fluid of this kind can have a large influence on the geochemical budgets of important solutes in the ocean because the flows are so large (from both Dorado outcrop and on a global basis).

            We will conduct an eleven dive operation with the submersible Alvin to collect fluids, rocks and sediment, retrieve experiments deployed in 2013, and measure temperature in the venting fluids and in the sediment. These data and samples will be combined to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop

Broader Impacts

            Undergraduate and graduate students and a junior faculty member (Hulme) will gain experience by participating in this program and through the development of ROV manipulated samplers and sensors. Results of this work will be broadcast in publications, theses, presentations (to scientific and lay audiences), and in K-16 curriculum development. The P.I.s have strong histories of involvement in educational and outreach programs at multiple levels. Wheat and Hulme are developing hands-on science-technology packages to engage K-8 students during week-long learning opportunities that include three technology-based activities per grade level and meet national science, mathematics, and language arts standards. Fisher will involve university students through USCS’s Institute for Scientist and Engineering Educators and Cal Teach programs. Wheat and Fisher are involved in the NSF-funded Science Technology Center for Dark Energy Biosphere Investigations (C-DEBI). Materials from this expedition will be incorporated in C-DEBI education and outreach activities, reaching a diverse audience that includes K-8 students in the Los Angeles area.

Science Activities

Additional Info

Stations:

Supporting documentation:

Shipboard Equipment

Shipboard Communication

CTD/Water Sampling

Critical CTD Sensors

Sediment Sampling

Sample Storage

Navigation

Navigation

Winches

Wire use and application

Standard Oceanographic Cables

Portable Vans

Specialized Deck Equipment

Over the Side Equipment

Special Requirements

Additional Cruise Items/Activities

Hazardous Material

Radioactive Material

Additional Information

Site Survey

Navigation

Vehicle Equipment

Elevators

Science Supplied Equipment

Hazardous Material

Additional Information

Checklist

Costa Rica

Master R/V ATLANTIS
Attn: Scientist's Name - AT26-24
IN TRANSIT
c/o Vasile Tudoran Transport
819 Ohio Ave.
Long Beach, CA 90804

Contact: Vasile Tudoran
Phone: (562) 882-5590
Fax: (562) 434-9800
Email: vtudoran@aol.com

Local Address for Large Shipments:

Master R/V ATLANTIS
Attn: Scientist's Name - AT26-24
IN TRANSIT
SERMAR SA
Aptdo 76
Puntarenas, Costa Rica
Attn: Manuel Fernandez
Phone: 011-506-2661-1529
Fax: 011-506-2661-2779

Manuel Fernandez, cell #011 506 8862 6787

Note: Agent and WHOI contacts should be copied on all communications. It is requested that shipment information of any equipment be communicated to the Agent and WHOI contacts

Checklist