QUESTIONS: Near-Seafloor Processes
The following is a list of questions, comments and hypotheses provided by Marv Lilley, Bob Morris, Jim Holden, Julie Huber, Susan Lang, and John Baross. We expect to explore these and more during Breakout Session #2 on Day 2. (See Agenda)
1. What is the contribution of chemoautrophy to deep ocean carbon fixation?
2. How do vents contribute to the diversity and dispersal of microbial communities in the deep ocean?
3. How much of microbial diversity and distribution in vents is deterministic vs. stochastic (down to the subspecies level)? How much does that matter?
4. What microbial processes occur throughout an entire eruptive cycle and at what rates? How do microbes behave/survive during quiescent periods and nutrient starvation? Is there recolonization by new (sub)species following an eruption or are (sub)species endemic to a particular location? What is the gain or loss of function between subspecies?
5. What are the relationships between different microbial species? When is there competition or cooperation? Does game theory apply?
6. What new technologies or approaches (at-sea or on-shore) should be employed to detect/understand microbes and microbial processes?
7. What is the connection between the subseafloor, plume, deep-ocean, and even pelagic/surface ocean for carbon, sulfur, iron, and microbes? What is the flux and fate of these biological and chemical species?
8. How much carbon is "looped" within the vent environment versus exported to the deep sea?
9. What are the mechanisms of viral infection and what proportion of the microbial community is susceptible? Do viruses carry host-derived auxiliary metabolic genes that could potentially impact microbial carbon utilization?
10. And a general subseafloor question: How isolated are individual vents from one another with respect to plumbing? Is there a subseafloor conveyer belt?
11. How does the temporal variability in chemical concentrations associated with an eruption impact fluxes into the deep ocean?
12. For the past 25 years the vent community has repeatedly discussed the kinds of data needed to come up with first order biogeochemical models of vents. We are still not there yet, but Axial presents an opportunity to think about how to integrate some of the geophysical, chemical and microbial measurements that might lead to a better understanding of spatial dimensions of the subsurface biosphere affected by the pre- and post-eruption events and particularly the horizontal and vertical dimensions of water movement.
13. Will the composition and distribution of the microbial community be affected by pre-eruption seismic activity and associated cracking dynamics, by the eruption event itself, and continue to change over short and long-term post eruption.
14. Are some of the Crenarchaeota and Korarchaeota that have been detected in sulfide structures but not detected in diffuse flow fluids present in high numbers during the eruption or for that matter during the period just prior to the eruption indicating that cracking events may be intruding into microbial habitats at much broader spatial dimensions than during post-eruption periods?
15. Are there isolated subsurface microbial habitats with organisms not yet seen that could be affected by the eruption and released into the event plume?
16. We are still not there yet, but Axial presents an opportunity to think about how to integrate some of the geophysical, chemical and microbial measurements that might lead to a better understanding of spatial dimensions of the subsurface biosphere affected by the pre- and post-eruption events and particularly the horizontal and vertical dimensions of water movement.
17. One hypothesis is that pre-eruption and the eruption event itself will release microbes from isolated habitats that include unique phyla.