23 deg 59.3S
Longitude: 69 deg 38.7E
Wind Direction: SE
Wind Speed: 12 Knots
Sea State 3
Swell(s) Height: 6-7 Foot
Sea Temperature: 80°F (26.7°C)
Barometric Pressure: 1015.3 MB
Visibility: 18+ Nautical Miles
Daily Update: Finding our first hydrothermal plume
By Amy Nevala
took one touch of the CTDs icy metal casing this
morning to know that it spent a chilly night collecting
data and samples in the waters deep below the Knorr.
evening when we arrived at 24° South, our first research
site, oceanographers Bob Collier and Marvin Lilley lowered
the Conductivity, Temperature and Depth (CTD) sensor to begin
searching for hydrothermal plumes.
Collier, it was the beginning of a long night of guiding the
CTD up and down in the water column behind the ship as it steamed
slowly across the research area.
Sitting at his computer just after 2:00 this morning,
Collier noticed a change in the traces of conductivity, temperature
and water clarity. A blip in the clarity at a water depth of about
2800 meters (about a mile and a half) told him that there were
more particles in that layer of cloudy water.
More particles is one sign of a hydrothermal plume.
He immediately collected a water sample for later analysis on board
By 8:00 am, the CTD had traveled over seven nautical
miles of seafloor. Nearly all the water sample bottles were full.
Crew members pulled the CTD up and chemical analyses of the water
this afternoon, Colliers suspicions were confirmed: the
water had high levels of the gas methane and the metal manganese
in the cloudy layer. These were more signs of a hydrothermal
We have lots of evidence that a hydrothermal vent
may be here, but some puzzles remain. Where is the source of the
plume? And is there more than one?
Just like smoke from a chimney bends in the breeze,
a hydrothermal plume can drift with the currents. This means that
the plume may not be directly above the seafloor vent. Now that
we have evidence of a plume, our next step will be to locate its
source - the seafloor hydrothermal vents.
This will happen when we return here in about a week.
Before departing tonight for the next research site at 25°19S, we deployed a current meter.
Scientists use the current meter to measure the speed and direction of ocean
Collected over the next week, data from the current
meter will tell us which way the deep ocean currents flow in this
area of the Central Indian Ridge. This could help us understand
which way hydrothermal plumes drift, thus offering another clue
of the vents location.
While chemical analyses continue and we review the
data we collected today, we will travel to our primary study site
at 25°19S. Tomorrow morning promises
to be exciting, as we launch the ROV Jason for its first trip ever to the bottom
of the Indian Ocean.
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