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scuba

Island Biogeography

By | Bahama Blue Holes, Cave Diving, Rebreather Diving, Sidemount Diving, Underwater Photo and Video, We Are Water, Women Underwater | No Comments

Tom Morris is a biologist and diver who lives in Gainesville, Florida and turned 70 years old on this expedition. His birthday present was a passport that he left in his car before heading across the Florida Straits by boat to join the team. He can now leave the Bahamas when the time comes, although he would rather remain in the Bahamas, where the pines sing, the bracken is tall, and every other plant is an aphrodisiac.

At its closest point, the Bahama Archipelago is a mere 50 miles from Florida, but it has virtually nothing in common with continental mainland animals, except for the ones that can fly (birds and bats). In fact, the only native land mammal found naturally in the Bahamas is the hutia, which is of South American origin. And there are only three species of snakes, all boas and probably descendants of a common ancestor, also of South American origin.   The same pattern holds true for frogs and lizards, and even insects.   So how is it that the archipelago is so biologically isolated from North America?

Some animal groups, notably the reptiles, with their waterproof skin and low metabolic rates, are able to survive relatively lengthy ocean crossings – think Galapagos and Seychelles Island tortoises and Komodo dragons. And I have personally seen diamondback rattlesnakes, which were at one time numerous on Florida’s barrier islands, floating miles out in both the Gulf of Mexico and the Atlantic Ocean, apparently none the worse for wear. But an animal floating or riding a log from Florida has to overcome two big obstacles to make it to the Bahamas; the trade winds and the Gulf Stream.

The trade winds are planetary winds, the largest and most consistent winds on earth, and the Bahamas lie directly in their path. The trades blow from an easterly direction over two-thirds of the time, pushing floating objects towards the mainland.

The wind blows from the west less than ten percent of the time. and is generally much weaker than the easterlies. But, even if favorable winds push a drifting animal towards the Bahamas, it will soon find itself in the Gulf Stream, and moving north at up to six miles per hour, toward the open Atlantic and almost certain death.

Animals and plants on islands have historical extinction rates far greater than their continental cousins. Everyone is familiar with the fate of many isolated island inhabitants, such as the flightless birds of New Zealand, who evolved in the absence of mammalian predators, and could not cope with human introduced rats, cats, pigs, and other animals. The Bahamian fauna face similar threats. The only animals I have seen dead on the Abaco roads have been cats and raccoons. Both invasive species are known to kill local animals, including the threatened Abaco parrot. And, perhaps more tragic, a scale insect from the mainland, brought in on Christmas trees from the mainland, are destroying the native Bahamian forests of Caicos Island.

But on a more positive note, the local newspaper, The Abaconian, reported today that a pregnant manatee from Florida, named Washburn, has been tracked crossing the Gulf Stream, and is now swimming in the waters of the northern Bahamas near Walker’s Cay (pronounced “key”). She arrived on Thanksgiving day. This is the same gal who was rescued from the cooling waters of Cape Cod, Massachusetts. Ain’t no trade winds or Gulf Stream gonna keep this girl from going where she wants to.

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Mapping the Labyrinth – Episode 11 from the Abaco Blue Holes Cave Diving Project with National Geographic

By | All Posts, Bahama Blue Holes, Cave Diving, Rebreather Diving, Sidemount Diving, Underwater Photo and Video, We Are Water, Women Underwater | No Comments

Steve Bogaerts is a cave diving instructor and explorer originally from London, England who has been living in Mexico for the last 18 years. Steve first visited the Bahamian island of Abaco in 2003 and has been making regular trips since then to explore and map the incredible Crystal Caves. In 2015 Steve and Brian Kakuk were able to complete a project years in the making by connecting Dan’s and Ralph’s Caves—two of the most beautiful and important caves on the island, and the caves that are the subject of our current survey project.

Expedition Blog 10 / Dec. 12 / By Steve Bogaerts

Today was my last day working on the National Geographic Abaco Blue Holes project. It has been a very rewarding experience both to work with this talented multidisciplinary team and to dive the amazing caves Crystal Caves of Abaco. As one of the original explorers of these caves, I am continually awed by the surpassing beauty Mother Nature can create. Unfortunately very few people will have the chance to experience the beauty of these caves firsthand. To be able to share that beauty and wonder with other people is one of our mains aims in this project.

One of the best ways we can do this is through cartography. Bringing back a map of your exploration allows other explorers and scientists to follow your path, to study and learn more, and most importantly to raise awareness of the need to protect and preserve this unique and fragile environment. Over the years many people have contributed to the exploration of the caves of the Bahamas, but unfortunately much of the mapping data remains missing or of poor quality.

During this expedition, we are starting a complete resurvey of Dan’s and Ralph’s Caves, which Brian Kakuk and I finally managed to connect together after many years of effort in 2015. The resulting connected system is properly known now as Dan’s Cave and is one of the longest island cave systems in the world. The area surrounding Dan’s Cave has moreover recently been designated a protected conservation area by the government of the Bahamas. Producing a complete map of the caves will help in these continued efforts to protect and preserve this unique and fragile natural wonder.

Cave survey, however, is a long, detailed, and laborious process. In addition to all the complex equipment a cave diver requires to safely conduct dives normally, surveying specifically requires many additional tools and techniques. The survey process begins by taking a GPS location fix at the entrance of the cave, which is then connected to the beginning of the permanent guideline that runs throughout the cave underwater. The GPS fix allows us to plot the survey data and the location of the cave on surface topological maps.

From this initial fix, every point at which the permanent guideline in the cave changes direction or depth must be fixed in place with a locking line wrap. Each one of these tie-offs becomes a survey station. The surveyor records the depth at each of these stations using a digital depth gauge and shoots the azimuth to the next survey station along the guideline using an orienteering compass. They then measure the distance between the stations using a fiberglass tape or knotted line.

All this information together with any important features or comments is recorded on an underwater slate. This basic information allows the survey team to create a “stick map,” or skeleton outline of the permanent guidelines installed in the cave passageways. This basic map can be further fleshed out by measuring the distance to the walls, floor and ceiling at every station and creating a cross-sectional sketch. Photos and video may also be recorded along with further geo-referencing at selected sites using a ground penetrating radar location tool called a “pinger.” All of this information is then downloaded to a computer survey program that creates a 3-D rendering of the cave with embedded links to photo and video of significant areas of interest.

Surveying an underwater cave is inherently limited by the amount of time that can be spent underwater on any one dive. This is further complicated in these particular caves by the saw-tooth dive profiles of the cave passageways (zig-zagging up and down), the need to surface slowly to allow for decompression, and the fragility of the highly decorated passages. In addition these caves are extremely complex with maze-like passageways that create a complex three-dimensional jigsaw puzzle of intersecting permanent guidelines. The desire to survey the cave accurately has to be balanced very carefully against the need to protect both the cave and the survey diver from any harm.

Having said all of that, it is a very satisfying feeling to return to base camp with full survey slates and to watch the cave map grow as you input the data and gain greater insight into the hydrology and geomorphology of the area. As the map has grown, so too has my desire to discover more of the secrets of the Crystal Caves of Abaco. I hope to be back soon to continue this journey of exploration and survey.

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Documenting Inner Earth – Episode #10 from the Abaco Blue Holes National Geographic Cave Diving Project

By | All Posts, Bahama Blue Holes, Cave Diving, Rebreather Diving, Sidemount Diving, Underwater Photo and Video, We Are Water, Women Underwater | No Comments

I have an odd business card. The title simply says, “Explorer.” In reality, I am the Explorer in Residence for the Royal Canadian Geographical Society, underwater photographer/cinematographer, writer, dive technology contractor, instructor and motivational speaker. In a nutshell, I do the creative things that help keep me underwater and most of the time, underground in water-filled caves. This hybrid career is an occupation that defies easy description and leaves me pinching myself every day with excitement over my rewarding work.

On this project I am reunited with friends with whom I have worked for over twenty years. It is a joy to be in the field with such a capable and effective team. We all fall into place and jump into roles that keep us extremely busy without too much direction. Whether you are washing the dishes, finding the next roll of toilet paper or blending life support gases, there is important work that keeps the expedition moving along. Everyone has to be a specialist of some sort but also a generalist who is motivated enough to see what needs to be done. Good teamwork means that everything runs smoothly and operations are safe and streamlined.

My specialty role involves capturing everything that happens with photos and video. That means I get to miss a few dishwashing sessions, but have a lot of tasks that need my constant attention. My day begins and ends with camera maintenance. Batteries need to be charged, dome ports polished, and O-rings, cleaned. Troubleshooting and making minor repairs are a constant issue. When you take cameras and lights underwater, things will go wrong and gear will get damaged regularly. I am running four separate cameras topside and three can be encased in waterproof, pressure-proof Aquatica housings. Each camera needs to record audio as well and without a sound guy on the team, I have to do my best to keep on top of that too.

When I hit the water I carry my life support equipment weighing approximately 150 pounds with an additional lighting kit of 45 pounds, camera strobes logging in at 22 pounds and two cameras that come to roughly 25 pounds. Each component is carefully weighted and trimmed so that it is relatively neutrally buoyant underwater. That means I have to push the mass through the water but not fight with the weight. Once I am submerged, my right brain fights with my left. I switch between video and still photography while monitoring life support swimming through an overhead environment. I also have to arrange a creative dance with my teammates and that is where the experience comes in. I am not able to talk to them, so we work on a combination of experience, telepathy and hand signals to orchestrate stunning pictures that tell the story of swimming through the veins of Mother Earth. On some television projects I have the luxury of underwater communications and a large support team, but this a raw, voluntary exploration. There is no budget beyond the reward of a job well done.

When I surface exhausted at the end of day, the job really begins. I rush back to our base camp, download footage and stills and start the editing process. Social media and news today is about relevance, so each evening we reach out to the world with a new expedition blog. We all take turns writing posts, but it is my role to create these short videos for you each night before I crawl into my hammock for a few hours sleep. I choose fun over polish in my edits and hope these simple nuggets of our work will bring you a little closer to understanding the life of an explorer. There isn’t a person on this team who would rather be anywhere else in the world right now. Whether we’re assembling activities for school kids, carrying equipment or surveying these stunning caves, we know we have the best job in the world.

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