Institute for the Study of Earth, Oceans and Space

Follow UNH professor and researcher, Karen Von Damm, and her crew on leg 6 of voyage 7 on the R/V Atlantis, a Woods Hole Research Vessel. The following log is Karen Von Damm's e-mail from the R/V Atlantis . . . Click on the images for a full view.

Research Log
East Pacific Rise; 9-10°N latitude

Sunday, January 13, 2002
Today is spent with the R/V Atlantis transiting south to the 9 North vent site. People are using the time to catch-up on their sample analyses, and sleep, from the first 5 dives.

Monday, January 14, 2002
Today is also spent in transit south. On Atlantis, we have our weekly fire and boat drill.

Tuesday, January 15, 2002
Today is the first dive in the area known as "9 North" or otherwise as the Venture Hydrothermal Field. There are numerous sites of hydrothermal venting in this area, which lie between 9 and 10 north latitude on the East Pacific Rise, which is part of the mid-ocean ridge system that encircles the globe. This first dive will take us to "Biovent", a high temperature black smoker that is surrounded by a lush biological community. This is the most northerly vent known in this area. The dive began about an hour later than usual, because of the time it took Atlantis to reach this site, after leaving 21N. Today is also what is known as a "PIT", or pilot-in-training dive, when an experienced Alvin pilot, a pilot who is being trained, and one scientific observer go to the seafloor. We will have a PIT dive, approximately every 5 dives, so there will be 5 of them on this cruise. Our first task at Biovent, before we even get to the seafloor is to locate a transponder that was left here on the previous cruise. Transponders are sound beacons that we place on the seafloor, usually temporarily, so that we can accurately determine where we are. Transponders are called back to the surface with a sound signal when we are done using them, but this one did not release as it should have, so we need to go cut it free. We see the transponder on its tether with one of the sonars on the sub at ~200m above the seafloor, and then follow the line down to the weight on the seafloor. We then cut it free to rise back and be recovered by Atlantis, while we go about our work at Biovent. We are using a different set of transponders than this one we release to determine our seafloor location here.

Wednesday, January 16, 2002
Today, Alvin dive 3751 is going to an area just south of where we were yesterday, to an area known as the "Biogeotransect"or "Transect"for short. This area is an area biologists, chemists and geologists have been tracking extensively since 1991/2 when volcanic eruptions occurred in this area. It is about 1.5 km long, we placed ~220 markers here in 1992, which we have been using to help us quantitatively determine the changes that have occurred since that time.

Thursday, January 17, 2002
Dive 3753 is the first on this cruise to an area that has not been visited since 1997. Hence we don't know what we'll find, and one of the first objectives is to see if the smokers here are still actively venting .. This is in the 946'N area, an area that was also affected by the 1991/2 eruptions. This area has been of less interest to the biologists, because for reasons we don't really understand, there are no tubeworms, etc. at some of these vents. One of these vents has been of particular interest to the chemists, because of the rapidity of the chemical and temperature changes observed in it. After landing on the seafloor, we quickly find the site of the L vents. The main vent here is now 15m tall! We find a marker left in 1996, as well as a temperature probe left in 1997 that is now firmly embedded in the chimney. The area is still quite active and we do some sampling, and some looking around so we can plan how mcuh we need to come back here. Before we leave, we place another recording temperature probe out, that we will leave for the duration of this cruise. We then head north to the A vent area. We first find it because of the white material that surrounds it. A vent is on a step in the west wall, and we can see the white from below. We go up and find a field of serpulids. The two old chimneys are no longer smoking, but there is hot water inbetween them, and we sample here.

Friday, January 18, 2002
Today we are back up in the Transect area around 950'N at other targets. There is an 11m high structure here that is covered by tubeworms, and at the top there has been an active black smoker. The black smoker at the top is much reduced in intensity, but we can still collect some samples here. At the base of the smoker, is a small vent that we have been sampling, and we do this as well. They then drive north observing, and sampling some of the rich biological communities found in this area.

Saturday, January 19, 2002
Alvin dive 3755 is back in the very hydrothermally active Transect, with targets we have not yet visited this cruise. One area of diffuse flow, near Marker 82, has been active since we started our studies here in 1991, but several years ago, some of this diffuse flow turned into black smokers. So the 82 area is now characterized by diffuse flow, and two high temperature vents Ty and Io. We are trying to understand how the fluids differ between high and low temperature in a single small area, and how this correlates with the biology - both "megafauna"(animals) and "microfauna"(microbes). This is an ideal site to do some of these comparisons.

Sunday, January 20, 2002
Today we are going to 933.5'N, a site which is south of the area at 9-10N where we know volcanic eruptions occurred in 1991/2. The dive was delayed approximately 2 hours when just before the scheduled launch a mechanical problem with the sub was discovered. We launched at 10:30, and found that we had a different mechanical problem than before, and decided to come back to the surface. We were back on deck by approximately noon, and the decision was made to do a quick repair, so we were back in the water around 1pm, and given the highly unusual permission to come up late. This time we made it to the seafloor and found E vent, with the marker we had placed there in 1994. We did not have time to locate D vent, our other target here. We collected a sulfide, and some water samples from E, which remain briny fluids. We left the bottom after less than 2 hours, and were safely back on the deck of Atlantis just before sunset.

Monday, January 21, 2002
Today Alvin dive 3758 is back in the area of the Transect, but with different objectives. There is only so much Alvin can carry in its basket at one time, which often necessitates several dives to an area to collect the needed samples. Today they sampled at a diffuse flow site, known as Biomarker 141 that we have been following chemically and biologically for 10 years, and then they went north to sample a high temperature vent adjacent to one we had previously sampled. They then went further north, just outside the area of the transect to another black smoker whose chemical evolution we have been studying.