Eifuku Vent

Latitude: 21.415^οN Longitude: 144.145^οE Summit depth: 500 m bsl

Scientists have recently discovered that the Eifuku seamount in the Mariana arc is active based on pre CTD operations and visits. During the visit, it was discovered that the seamount is composed of lava domes, striated boulders and an exposed dike in the crater wall. In addition the summit showed diffuse hydrothermal activity with fluid temperatures reaching about 16°C. Among the observed living organisms barnacles were dominated while there were other demosponge, seastar and bamboo coral (Okeanos Explorer ROV dive summary 2016)

Table 1: Operations history for Eifuku vent

Ship/ Platform	Operation	Year	Dive Number	References
EX1605/Deep Discoverer	CTD, Scanning sonar	2016 June (Leg 3)	8	Okeanos Deep Discoverer 2016

Table 2: Vent activity and host rocks

Activity and host rocks		References
Activity	Active	Okeanos Explorer 2016 dive summary
Host Rocks	Not defined	Okeanos Explorer 2016 dive summary

Table 3: Vent fluid characteristics:

Vent Fluids		References
Temparature (°C)	16.33	Okeanos Explorer 2016 dive summary

Table 4: Vent biology:

General name		Phylum	Genus/Species	References
Eukaryota	Barnacles	Mollusca	Nudibranchs	Okeanos Explorer 2016 dive summary
	Barnacles	Mollusca	Kaloplacumus	Okeanos Explorer 2016 dive summary
	Demosponge	Porifera	Okeanos Explorer 2016 dive summary
	Bamboo coral	Cnidaria	Okeanos Explorer 2016 dive summary
	Sea stars	Echinodermata	Coronaster	Okeanos Explorer 2016 dive summary

Images:

Okeanos Explorer 2016 dive summary

Video Links:

Long-spined sea urchins (note: search “Long-spined”).

Cruise Reports:

NOAA Okeanos Explorer 2016 https://docs.lib.noaa.gov/OEDV/Okeanos_Explorer_2016_EX1605/Leg_1/doc/rov_dive_summaries/EX1605l1_Dive12_Summary_20160502_FINAL.pdf (accessed: 07/05/2016)