Sunday, April 29, 2007
Series of Posts for April 25 - April 29.
Dixon Hill Lighthouse on San Salvador
This is a remaining lighthouse on San Salvador. This has provided navigation aid for ships for 120 years. For over 500 years, the reefs of the Bahamas have caused problems for sailors. Many ship wrecks have occurred. For over a hundred years, a major source of income for the inhabitants was salvaging cargo from ship wrecks. This was very important to the early economy. Keeping lighthouses in good repair was counter productive to the local economy.
A closeup of the kerosene light and lens
The light of lighthouse is shown here. It is burner for kerosene. This produces a strong light which is then directed in a beam by the lens that you see in the background.
The mechanism which turns the lens
This is the mechanism which turns the lens for the lighthouse. The next photo explains the energy source.
Weight system
This is equivalent to the weights which provide the energy for grandfather clocks. This weight is raised by a hand crank to near the top of the light house. The force of the weight causes the mechanism to turm rotates the lens of the lighthouse. Over a period of hours, the potential energy of the weight is used to turn the lens.
Entrance to Lighthouse Cave
The island of San Salvador (like all of the Bahamas) is made up of calcium carbonate from coral reefs. The calcium carbonate is slowly dissolved by rain water, resulting in many caves on the island.
Ladder needs replacement
I believe we need to buy a ladder of the appropriate length, paint it purple, and send into to San Salvador for a replacement.
Group making their way though the cave in fairly deep water.
Making ones way through a cave passage over half filled with water can be unnerving -- but what till you see creatures you might see in the cave.
Student talk about politics in the Bahamas
The Bahaman political system was discussed in detail. They have a parliamentary form of government made up of 2 houses. Parliamentary elections are currently occurring in which all members are currently running for a 5 year term.
A rally of the FNM party
This political rally by the FNM party was held about a half mile from the Gerace Research Center. It was attended by several of our students.
Jumping Off "The Thumb"
"The Thumb" is a projection of land into the Ocean. The ocean has undercut the calcium carbonate rock and this provides a "jumping-board" like projection about 15 feet above the water. Getting a good photo with a digital camera which has a slight delayed action takes some skill. Here are 3 fairly good pictures:
Religion on San Salvador
A student talk which included a demonstration of a animated hymn sung at a church service.
Entrance to Owl's Hole
Owl's hole is a natural formation near the southern end of San Salvador Island. It was so named because an Owl used to inhabit it.
Stalactites in Owl's Hole
Although Owl's is primarily a 30 foot vertical shaft, it has the characteristics of a cave. It was probably formed by the dissolution of the calcium carbonate by water. Furthermore, stalactites have formed on the side wall.
Core Drill Samples
Core drill samples were taken and were used to determine the age of the rock formation as 300,000,000 years old.
Columbus Monument
This is one of the places on the island that commemorates Columbus' first landing on the island. (They all couldn't have been first, but that is a detail.) The inscription is "This plaque was given by the government of Spain on the occasion of the visit of the replicas of the Christopher Columbus Caravels on February 10, 1992, in commemoration of the first landfall at San Salvador in 1492."
Fossilized Coral
The islands of the Bahamas were made by coral reefs. This particular fossilized coral is visiable in downtown Cockburn Town. It is estimated to be 250,000,000 years old.
Faculty Members (Powers, Bezotte, Lanterman) Sitting on Coral
After some discussion, we were able to persuade most of the students that the coral was older than the faculty.
Shark ! ! (End of April 25 - 29)
This photo is more convincing than the prior photo taken 8 days earlier.
Tuesday, April 24, 2007
April 24
- We retrieved traps we had placed the day before which trapped sediments in various locations which varied in the amount of sea grass present.
- These samples were examined and then processed for quantification after drying.
- Lisa gave a lecture on ocean sediments.
- Students examined some of the samples under a microscope.
- We traveled to the far end of the island to see bats in their natural enviroment.
- We went to a beach to obtain shell samples for later identification.
- We walked a half mile to a political rally that was to start at 7 pm. Because it hadn't started by 8:20, we left. It finally started at about 9 pm and is still going as it approaches midnight. (The music is nearly too loud even at a distance a half mile.)
An item I left off from last night. We were able to observe the craters on the first quarter moon last night. We also saw the rings of Saturn and probably its moon Titan. In general, the students are impressed with the astronomy part of the course.
I have been able to repair the telescope we are borrowing so that it is quite useable. More about this another night.
Below, see the pictures of today's activities.
Students attending a lecture
Students have been tolerating, enduring, and mostly enjoying several hours of lectures most days.
Digital Camera
I was able to bring a digital microscope camera which could hook to a laptop and display the little ocean critters we found. It also has the capabilities of capturing a still photo and video. You will next see some still photos. (I don't know how to upload video.)
An foraminifera in some small sand particles
An foraminifera in some small sand particles, originally uploaded by powersdale.http://www.ucmp.berkeley.edu/foram/forammm.html .
An unknown critter found in the sand collected in the ocean.
We will have the student identify this small creature.
Crossing the road with care
In spite of the interstate sign, this road seldom has any traffic -- and at 80 degrees, we didn't see any snow removal equipment.
Entrance to Alter Cave
This cave has some interesting bats in it. I wasn't able to photograph them with the lighting we had available. We didn't use a flash because that could make some of them fly. Their flying could result in some of the students screaming. Their screaming could result in more bats flying -- and thus escalating into complete mayhem. So I didn't a flash and didn't get a useful photo of the bats. I believe some of the others' cameras were able to get a good photo without a flash and I might upload one if I get one.
A couple of bats did fly, but no one screamed and everything went fairly smoothly.
There were some large roaches crawling on the walls
We didn't bother them and they didn't bother us.
We went in search of the Dripping Rock Bat Cave (Start of April 23rd)
We went in search of the Dripping Rock Bat Cave, originally uploaded by powersdale.The roads are somewhat marked, but they appear on no publicly available maps. We were getting close when the next post down happened.
The Truck broke down
The truck got stuck in reverse. Probably something wrong with the linkage. Some students walked about 1.5 miles to the beach. Two students and I hiked back up the road to get help and were offered took rides to a pub. There we were not able to make contact with the Research Center by either telephone or shortwave radio. Phone systems etc don't necessarily work well on the island. (The electricity was off on Sunday for 4 hours also.) Adam Breslin was able to get a ride back to the Center and help was sent in the form of a truck for the students plus a repairman for the broken down truck.
The two students and I were finally retrieved from the pub where we had played dominos. (We were practicing because the locals take this game very seriously.)
April 22 - Sunday
Mermaid Team on Truck (Start of April 21 post)
Here is the first "Mermaid Team". This is after a successful trip to Mermaid Pond, they are loaded on the truck and ready to return.
I show you this first so you know who were willing to go on this adventure -- and to assure you everyone was happy when we made it back. Read the posts further down to get more information.
Getting a sample of the layer of the flocculent
There is an organic flocculent layer at the bottom of the pond. Only scientists would be interested in wading in and getting some.