Observatory science is VERY USEFUL to investigate the following:

• The chemical and biological response to episodic volcanic and hydrothermal events;

• The formation of event plumes;

• Subsurface biosphere;

• Marine food webs on the seafloor; and

• The linkages between geological, biological, and chemical processes in ocean crust.

Observatory science is USEFUL to investigate the following:

• Fluid flow on ridge flanks; and

• Simultaneous environmental variability in ridge crest, flanks, and convergent margins.

To address the science where observatories are very useful, development or improvement of the following sensors is needed:

• Chemical, biological, and flow-rate sensors that can operate at high temperatures for long-term deployment without servicing;

• Fluid and biological samplers suitable for long-term deployment;

• AUVs, drifters, and other instruments for use in rapid-event response;

• Downhole sensors for use in boreholes;

• Instruments for acoustic event detection (such as the SOund SUrveillance System [SOSUS]); and

• Advanced capabilities for drilling into ocean crust.