Hello Friends of the Loggerheads!
Dr. Standora has sent us new data again this week. All of this new data is provided below, so be sure to chart the movements of the turtle transmitters and compare them to the movements last week. Do you notice any interesting changes?
In last week's update, we challenged you to learn about the Sargasso Sea, and tell us where it is located, why it is unique and what there might be in that area for turtles to eat. Many students sent in answers and we have put those below.
As you will see in the students' answers, the Sargasso Sea is a large calm area in the center of the North Atlantic Ocean. The Sargasso Sea is surrounded by ocean currents on all sides, which circle it in a clockwise direction. At the west and north edge is the Gulf Stream moving to the northeast; on the east and south is the North Equatorial Current, moving to the south and west.
The edges of the Sargasso Sea, where the surrounding currents go by, is a unique area that some scientists believe is important to young sea turtles. Along these edges, long "rafts" of sargassum weed drift along, and it is thought that after baby turtles are born along beaches, they swim out into the ocean, get into a current such as the Gulf Stream and eventually end up in a sargassum mat, where they stay and drift, sometimes for years,until they grow up.
Scientists have found that in these sargassum rafts, and in the converging currents nearby, there is plenty of food for the turtles to eat even though the ocean is so very deep. In the sargassum mats, scientists have found a very diverse collection of food for the turtles. According to the late turtle expert Dr. Archie Carr, the sargassum mats have "many kinds of little fishes, crustaceans, worms, molluscs". Dr Carr also thought that converging currents alone would also draw in a large amount of other foods, so the young turtles might find food even if there were no sargassum rafts.
We recently asked Dr. Standora about Turtle #11462, which has moved out into the Gulf Stream, and appears to be close to the north edge of the Sargasso Sea. We asked him why it is out there and what it might find to eat. With Dr. Standora's information, you can see the connection between the information above and the loggerheads.
According to Dr. Standora, "The turtle (#11462) is now in one of the major fishing areas of the world." Dr. Standora thought it was "Probably feeding along the surface as they did when they were younger. It is a very biologically active area so there is probably an ample food supply. At the higher latitudes parts of the Gulf Stream will break off and leave cores of warm water containing tropical fish. Our turtle is probably enjoying water warmer than you would expect for that latitude."
For this week's challenge question,we want you to think about why data for some of the turtle transmitters were received far more often than data for other transmitters? For instance, look at the data below--why are there so many data transmissions for Turtle # 09037, and only one for Turtle # 11462? To help you think about this, review the Loggerhead Migration Update from Feb.7,1996,where Dr. Standora talked about the three things that must happen before the satellite can receive a transmitter signal. Then, answer the challenge question:
Challenge Question # 55:
"Why would data for some of the turtle transmitters be received far more often than data for others?"
Instructions on how to respond to this challenge question are shown below.
New Turtle Data
Turtle # 09037
Mar. 08: 37.522N,67.425W
Mar. 09: 37.533N,66.829W
Mar. 09: 37.543N,66.762W
Mar. 10: 37.607N,66.220W
Mar. 10: 37.631N,66.065W
Mar. 11: 37.811N,65.528W
Mar. 11: 37.838N,65.476W
Mar. 11: 37.846N,65.446W
Turtle # 09038
No Data Received
Turtle # 09039
Mar. 08: 40.271N,55.049W
Mar. 08: 40.296N,54.934W
Mar. 10: 39.744N,53.987W
Mar. 10: 39.692N,53.981W
Turtle # 11462
Mar. 10: 39.791N,49.465W
(Note: The data in last week's March 20, 1996 loggerhead update should have been labelled as data for March 1, 2, 3 and 4, rather than February. The data is itself correct. We apologize for any inconvenience this may have caused.)
Students Answers to Challenge Question # 45:
From WISCONSIN:
Hi we're from Drummond in Northwestern WI. We're in 7th grade. We're in
algebra 1/2. The Sargasso Sea is the calm center of
the clock wise turning sub-tropical gyre that dominates the North Atlantic.
It is located approximately between 20 degrees and 35 degrees north
latitude. It is bounded on the west and north by the Gulf Stream and on
the south by the North Equatorial Current. The Sargasso Sea is unique
because the currents seem to go around it and the algae seems to settle on
top of the water. It is very calm.
Drummond High School (dhs@win.bright.net)
From ONTARIO:
The Saragasso sea is located in the southern part of the Atlantic
Ocean. It extends from the West Indes to Azores. What makes it so
unique, is that the water there is very still, and there is no wind.
Often ships and vessels have stopped in the sea and they would have to
row the ship, until the wind caught up. We found this information in
the New Book Of Knowledge Encyclopedia.
Bye for now, Ashley, Rose and Steph.
Scott Young Public School syoung@web.apc.org
How to Respond to Journey North Challenge Question # 55:
1. Address an e-mail message to: jn-challenge@learner.org
2. In the Subject Line of the message write: Challenge Question # 55
3. In the body of the message, give your school's name and location and answer this question:
"Why would data for some of the turtle transmitters be received far more often than data for others?"
We'll share your ideas and those of other students in future reports. You can also see students' answers to Challenge Questions on Journey North's WWW site.
The Next Loggerhead Turtle Migration Update Will Be Posted on April 3, 1996.
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