June 17 - June 24, 2007
June 19th, 2007
Kristina and Laura R write:
Today was our second day on Pioneer Seamount, the northernmost station during our expedition. We deployed the ROV Tiburon on time at approximately 6:30 am, hitting bottom at about 8 am. Our transect began at a depth of 1032 m and ran northwestward to shallows at 850 m. The peak of Pioneer Seamount is located in the oxygen minimum zone of the Pacific, and hosts a colorful variety of species of marine life.
Today we observed more about the ecology of the corals. In contrast to yesterday, where corals dominated the deeper regions of Pioneer, the shallower depths visited today contained dense aggregations of sponges, such as this enormous goiter sponge (approximately one meter across) at 900m.
Rock samples were also collected throughout the dive to provide insight on the type of volcanism occurring at Pioneer Seamount. The highlights of the rock samples collected included vesicular basalt that we thought during collection was volcanic sandstone, and a basalt with geochronological potential.
Overall, these dives were a great success. We have
now finished our objectives at this site: exploring the volcanic cones
on the shallowest part of the seamount and collecting coral samples from a range of depths to
anchor the northernmost climate signal we have from the California
Current. We observed deep-sea
corals at depths ranging from 1490 m to 830 m. We also observed sponge
meadows and fields of corals. The materials collected and animals
observed here will provide the scientists on board the Western Flyer with a plethora of new information with which to study the deep sea. We are now steaming south toward Davidson Seamount.