24 deg 43.5 S
Longitude: 68 deg 49.4 E
Wind Direction: E
Wind Speed: 17 Knots
Sea State 3
Swell(s) Height: 5-7 Foot
Sea Temperature: 80°F (26.7°C)
Barometric Pressure: 1016.1 MB
Visibility: 18+ Nautical Miles
Daily Update: Welcome to 24 South
By Amy Nevala
We celebrated tonight, for two reasons.
First, after two and a half days, most of us no longer fall when the ship rolls -- we now walk with that strong, wide-legged swagger of veteran sailors. Second,
we arrived this evening just before a dinner at an important coordinate -- 24°00S
69°40E, our first research site on the Central Indian Ridge.
We picked this site because Japanese and German scientists, who
were here on expeditions between 5 and 12 years ago, detected
hydrothermal plumes in a small valley on the ridge.
with no sign posted in the middle of these blue waves saying Welcome
to the Hydrothermal Plume Valley, how did we know that
we came to the right place? We made a map of the sea floor
to locate the valley using Knorrs multibeam sonar
The system works through sound-producing sources
mounted across the ships
hull. All 120 sources transmit a beam of sound energy that bounces
off the ocean bottom and returns to the ship. Computers then convert the time
it takes for sound to travel that distance to water depth. Finally, computers
plot the data on a chart.
Spreading out the site map we brought next
to the one we just made, we saw that the sea floor hills and
valleys matched. That was our sign that we were in the correct
Now our research can begin. Tonight while others
sleep, oceanographers Bob Collier and Marv Lilley will lower
the CTD sensor (Conductivity-Temperature-Depth) to begin a technique
called a tow-yo to search for hydrothermal plumes.
Tonights survey will help us to decide if this site is a good one to return
to later in the expedition to search for seafloor vents.
[Back to top]