New lava (rumbleometer stuck in flow) SE rift zone
Technology (ROV, ships, etc.)
Preliminary Plan for the 1998 NeMO Expedition
The 1998 NeMO expedition will be on board the NOAA ship Ron Brown from August 24 to September 20. The ROV ROPOS will be the primary tool for observing and sampling the seafloor as well as for manipulating other instrumentation.
The research cruise consists of 23 dive days and 3 transit days. Below is a summary of the scientific objectives that were funded by the supporting agencies. In addition to these goals, there will be interest in documenting any changes resulting from the earthquake swarm and intrusion/eruption that occurred at Axial in January 1998.
The scientific research during the NeMO cruise is multi-disciplinary. That means that scientist from many different fields (geology, chemistry, biology, oceanography, geophysics) are all working together toward a set of common goals. Nevertheless, specific objectives can be broken down by discipline:
Goals by Discipline:
The chemistry program aims to find relationships between the temperature and chemical composition of selected hydrothermal vents with the kind of microorganisms thriving in them. The specific aim is to understand what the subsurface environment is like.
Objectives & key questions:
2) Look for evidence of chemical reaction or metabolism by microorganisms within hydrothermal fluid samples.
3) Culture microbes from well-characterized environments.
4) Assess diversity and population structure by genetic techniques.
5) Relate chemistry and microbiology to geological structure and plumbing system.
SUAVE in situ: CTD, Fe, Mn, H2S, (pH)
Transition metals and trace elements, frozen samples for NO3, DOC (at UW)
Osmosamplers (Year-long deployments)
Extensive use of fluid sampler, SUAVE
The microbiology/ecology program will focus on the communities of larger animals that live in and around hydrothermal vent sites.
Objectives and key questions:
Does Species composition vary markedly over the four major Axial sites?
How does the Axial species pool compare to Cleft and CoAxial?
What does temporal variability look like at Axial?
2) Community structure with respect to water parameters:
Correlate information on water/microbial conditions and animal distribution over the caldera
initial focus on the polychaetes as they display variability over the seamount
The microbiology program will characterize the different vent habitats above the seafloor and relate this to the microorganisms living there.
Map high temperature habitat with SUAVE
30 min. Video
Time-lapse camera deployment for a day or two
2) Microbial Sampler
Measure low-temperature microbial abundance and diversity
Important aspect of vent community characterization
Some time for testing and adjusting system, in conjunction with SUAVE surveys
3) Habitat Variation and Stable Isotopes
Interpret ranges of C and N isotopes in select species in different conditions of venting
Collection of faunal samples where SUAVE and/or fluid samples taken (also fits with Tunnicliffe group goals)
4) Biomineralization Processes
Mineral, chemical, and microbial characterization of oxide mounds around ASHES
Mapping of mounds
SUAVE, time for collection of samples (with PacMan, Slurpgun, manipulator)
The geology program will look at the different kinds of geologic structures that host hydrothermal vents.
Dedicated dive time, surveys done up to 10-30 meters altitude using digital camera and scanning sonar with good navigation
2) Time-series of horizontal strain changes on Axial Rift zone(s)
Survey 1996-98 site of extensometer deployment
Recover extensometers plus refurbish
Redeploy 5 extensometers (1 year), probably at same site
3) Geologic/hydrothermal time series
Look at nature of and coherence of temperature changes in selected hydrothermal vents with seismicity (recorded during a separate OBS experiment by SIO researchers) Do earthquakes cause changes in the output of individual vents?