Today

ABE's cradle has looked very lonely today. Around midnight he was put into the water for the last dive of the expedition, his longest dive yet. So there were no amazing heavy weather recoveries today, just everyone quietly going about their data collecting responsibilities. Which, after all, is why we came out here!

At the same time that ABE was busy flying his tracks approximately 80m above the seafloor, the CTD package was being pulled around the perimeter of the "box" of the Main Endeavour Field and oscillating between 120 and 250m above the seafloor. It was critical that the winch operators keep careful control of the CTD's depth so that it would not come too close to the depth where ABE was flying. This particular combination of measurement devices working at the same time is a unique opportunity to measure the heat flux above the seafloor and the geometry of the plumes in the "curtain" around the box. This should give the best picture yet of the field's heat input and simultaneous loss in neutrally buoyant plumes.

The teachers have drawn inside themselves as the deadline for their projects looms less than 36 hours away. Of course, they had to stand their regular watch, but Diane came to the assistance of some by relieving them of their duties so they could concentrate on other things. Other members of the science team are also working intently in order to make presentations of their findings tomorrow. Even with deadlines coming up soon several of us took advantage of the beautiful weather to spend time outside reading, writing, or just catching some much-needed rest.

Just a little before sundown a Fork-tailed Storm Petrel joined the Black-footed Albatrosses that have been our regular companions, and a cluster of six salps floated past the stern.

Around 22:00 Christian broke out his stash of styrofoam wig heads to present to us. This is in preparation for a much-anticipated chance to send styrofoam objects down to some yet-to-be-determined depth where they will be crushed by the great pressure of the water column. Typically, the teachers have sent styrofoam cups down with various submersibles only to have them brought back up at a fraction of their previous size. The wig heads, now in various states of decoration, are proving to be a big hit. Things can get pretty silly around here late at night.

At 23:00 we are at N 47^o 56', W 126^o 05'.
Temperature = 15.3^oC; Sea Surface Temperature = 16.3^oC; Wind = S 0.1 knots; and the atmosphere inside the ship is mellow. The end is in sight!

Science and Education

"Water, water, everywhere and not a drop to drink" --- Rhyme of the Ancient Mariner

All around us for seventeen days now, we have been on the ocean. Fortunately, we do have water to drink. (See science and education section of August 16 Log for a description of the ship's capability to take the salt out of the ocean water). We know that ocean water is salty, but what does that really mean? Salinity is the total amount of solid material that is dissolved in water. Does that mean that we can make seawater if we dissolve table salt (sodium chloride) in fresh water? Actually, if you do that, you will only have one component of seawater. Ocean water includes various salts, metals, and even dissolved gases. Six elements account for over 99% of the dissolved solids in seawater. They are chlorine, sodium, sulfur, magnesium calcium and potassium. (See if you can find these on your periodic table. If you don't have one at home, checkout any Chemistry book). Another 89 elements have been identified in seawater, but in extremely small amounts.

There are various ways to measure the salinity of water. You can take a measured weight of seawater, let the water evaporate, and then weigh the salt which is left. This method is not the most accurate, although it works very well in the your kitchen or school laboratory. With advanced oceanography instruments, it is done by measuring electrical conductivity. This is the ability of a substance to transmit electrical current. Electrical conductivity of ocean water increases as the salinity increases. The more dissolved substances in the water, the better the water transmits electric current.

So for days, we have been receiving data from the CTD. By determining conductivity, we can determine the salinity. This is the reason for the "C" in CTD. Do you know what the "T" and the "D" stand for?

Personal Impressions

Russ McDuff, Chief Scientist; Professor of Marine Geology, University of Washington

Exercise

I'm not one to follow an exercise regimen. Not that I avoid exercise. I play squash regularly. In summer I do quite a bit of mountaineering and in winter I ski as often as possible. I even spend some time on our weight machine a couple of times a week. But to get on the Nordic Track at home, every day, no way.

At sea this is a problem. It's way too easy to get three square meals a day, the ship doesn't have a squash court, the four levels between the main lab and the bridge are a sorry excuse for a 4000' climb. I just have to bite the bullet and get on one of those exercise contraptions.

This trip I've adopted Fritz's exercise bike. After all, people tell me that biking would be good for my sorry knees (a legacy of too much mountaineering). It looks like a simple device. You can move the seat up and down, and adjust the resistance, and turn on the digital readout to find out how fast you're peddling, how far you've gone, and how many calories are burning away. So I start pedalling. It says I'm going 60 rpm. I ask Fritz how many rpm should I be going. He says he does 80. So I speed up. So far so good. I fiddle with the digital readout. It says I'm burning 7 calories/minute. I know that's not enough. I ask Fritz how much resistance I should use. He says he turns the knob four full turns. I need to add two turns. That's the ticket. I'm pedalling a little more slowly, but the calorie meter is up to 11 per minute. I look at the elapsed time. 7:25 and counting. I ask Fritz how long I should ride. He says he rides 20 minutes. 20 minutes? I'm bored. I decide to watch my feet going around and around. 9:45. Beads of sweat tell me its having the desired effect. I fiddle with the readout again and watch the mileage. Then the calories. Then my feet. Mileage, calories, feet. This data gathering part appeals to the scientist in me. Then even that becomes boring. And finally I'm done.

Amazingly, I've come back every day and done it again. The hardest part is between the 2nd minute and the 19th. I know I only have three days to go now. This isn't going to be a hard habit to break...

Questions and Answers

Question
Diane Langmuir, 7th and 8th Grade Science Teacher, New Jersey

It's wonderful to be able to learn so much about the science, the people, and the daily life on board a research vessel. So grateful for the effort you all are putting into the Revel web page.

I was wondering what are some of the research projects that the teachers and the students have chosen to explore?

Answer
Elaine Paulishak, Science Teacher, Throop, PA

Hi, Diane,
Thank you for your interest in the REVEL project. As teachers on this expedition, we are really the students because we are immersed in scientific research endeavors that are new to us. We are fortunate because on this particular adventure, we have been exposed to so many different kinds of instrumentation and measurement techniques. We have ABE and the CTD both taking measurements of various characteristics of the hydrothermal vent fields. Although the main goal is to study heat flux associated with vents and their consequent plumes in the Main Endeavour Field, we have also had the opportunity to study some other venting areas along the Juan de Fuca Ridge. In order to evaluate what is happening, the scientists need to measure temperature anomalies, density, backscatter, redox potential, conductivity (salinity), bathymetry and depth (to mention a few). So, I hope this conveys that in trying to determine what research projects to choose, we had a wide range of information and technology at our fingertips.

To answer you question more directly; here are the titles of the projects that we chose:
Tom--Study of a transect of the Main Endeavor Field in order to describe the plume characteristics based upon the information recorded by the CTD rosette sensors
Joy--Project to engage students in the study of science using a multimedia presentation developed onboard with ABE as a focus
Melissa--Study of redox potential versus backscatter to see if there is a correlation that will lead to a better understanding of plumes
Evan--Historic comparison of the Endeavour Field changes over time using GIS software (Arcview and GRASS)
Elaine--Analysis of the Northern and Southern boundaries of the MEF with relation to their temperature anomalies versus depth

Question
Diane Langmuir

How will they follow up on this work and share it with others when they return to their 'other' lives on land?

Answer
Tom Lee, Science Teacher, Battle Ground, WA

One part of our responsibilities as REVEL teachers, Diane, is that we will share our experiences not only with our students but with our colleagues and community members as well. That is just a formality: I think it would be hard to keep these teachers quiet about their experience aboard the Thompson. Of course, our students will benefit most directly and most immediately, but we also plan to make presentations to our local school boards and school faculties within the next few weeks. Several have informed their local newspapers of this opportunity. Our Educational Service Districts (ESD's) should expect proposals for teacher inservices. The Washington Science Teachers Association conventions have been the sites of previous REVELers' workshops and will continue to be, as will the other states represented here. Certainly the National Science Teachers Association national conventions have already benefited from REVELers' presence. Articles in science teacher publications, such as The Science Teacher and Currents, are planned within the year. One of the teachers, Evan, is a Learning Space member and plans to work through that venue to make materials available to teachers, as well as work in conjunction with museums and observatories using REVEL as a resource.

Send in questions about this cruise to revel@ocean.washington.edu between August 3 and August 20, 2000

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