cruise plans technology education participants calendar
         
         
 
Student Reports:
June-Aug. 2000
S M T W T F S
16 17 18 19 20 21 22
23 24 25 26 27 28 29 
 30 31 
 1
 2  3 5
 

NeMO Date: July 29, 2000
Ship's Location:
45 20'N 129 55'W

 
         
         
 

Student's Report:
Greetings once again from NOAA Ship Ronald H. Brown. This is Darin and Vito. We have switched from the bridge so that we can work with the PMEL oceanographers. We want to fill you in on what we have been doing.

The weather has been exceptionally good for us the last two days. The water surface has been smooth with slow moving swells that quietly pick up the ship and set her down. This rocking motion is hard to describe but it makes you sleep well and reluctant to get up in the morning. Today we are a little tired because we stayed up so late watching the marine life in the lights on the "fan tail" (back of the ship). We were visited by a large blue shark that loomed up from out of the darkness. It appeared as the CTD was being lowered for another tow-yo.

The crew has been relentlessly pulling the rosette of sampling bottles and instruments up and down, into and out of the hydrothermal vent plume along the South Cleft Section of the ridge now for days. Mile after mile, the stainless steel reinforced carrying device (rosette) has performed diligently. The ship has a pretty good "eye" on the bottom but sometimes there are benthic features that suddenly appear and it's too late to get the CTD out of harms way. That's what happened yesterday but it's like Operations Officer LT Boland taught us, it's good to have a back-up plan. They quickly replaced the old rosette that was badly bent with a second one and transferred the bottles and instruments to it.

The crew has resumed the tow-yos and we are working with Dr. Baker in the lab. We have been plotting points on a bathymetric chart (bottom contour chart) of the Axial Volcano area. If you remember that a few days ago, we were tow-yoing and vertical casting all around the Axial Volcano. Each time a water sample was taken, Dr. Baker marked a point on the chart where the samples were taken. Currently, we are plotting the latitude and longitude of each of those locations. We note the Niskin sample bottle number that was closed at each of those points on the computer and submit to Dr. Baker a printout of our findings. Bathymetric charts can be used in navigation like surface charts. If you ever loose your way at sea because your navigation system failed, bottom contour charts can get you home. They show underwater features in great detail depending on the scale. These charts have a contour interval of 5 meters and are very detailed. They are colored to enhance sudden rises in benthic features so you can look at them to get a better understanding of characteristics on the sea floor. Drawing lines on a chart that connects points of equal depth makes bottom contour charts. It's kind of like when you made "connect the dot" pictures in workbooks that you may have done in elementary school.

Points of depth are determined with an echo sounder. This is where a beam of sound is projected straight down to the bottom through a transducer. After the sound wave hits the bottom, it bounces back up to a receiver in the hull. Since we know how fast sound travels through the water, all we need to know is how long it takes to go and come back to the ship. That information is then calculated to give us depth. The echo sounder on the Brown is louder as you get closer to the bottom of the ship. It is always on and sounds like a bird chirping. We were embarrassed earlier in the cruise when they first turned on the echo sounder. We looked around the ladder wells and rooms for a bird that we thought may have accidentally flown in while we were berthed in Victoria. The captain toyed with us a bit but soon explained what it was.

Tomorrow is my (Darin) birthday and I am looking forward to it. Our Chief Steward, Lito says if we have calm weather, maybe we'll barbecue some of those squid we caught last night. I hope so but we'll have plenty of burgers and hotdogs as well. We will probably have to scrub extra dishes and make more work for our selves but it will be fun. Students at sea may take a break for a day or two because we are all writing an assignment from our senior English teacher. We are writing short stories about a fictional person that goes to sea for the first time on an oceanographic research vessel. This is taking a while but the plot is pretty easy to imagine. Until then, we wish you well and hope that your running lights burn bright.

 


The Reefdogs out enjoying the good weather.