Archive for June, 2010

What is an Atoll?

Uncategorized | Posted by admin
Jun 04 2010

Amanu, Tuamotus 4 June 2010 17.8803S 140.7881W (I’m cheating a little this is June 1 position, we’re farther north in the lagoon now, but I’m too lazy to turn on the navigation program and look up our current position)

June! Wow! Summer for most of you, while here the weather is getting cooler as we climb up again in Latitude. Last night watching the sunset in the cockpit, I had the strangest sensation, one not felt in weeks – chillbumps! They disappeared, as soon as I went below to show everyone, but for a minute I actually had chillbumps. It’s hot in the Marqueses, and descending 7 degrees latitude, lowers the temperature as well. I don’t know exactly by how much, we don’t have a temperature gauge on board, but while you pull bikinis out of the mothballs, we’re getting out the short sleeve shirts since a swim suit is not always quite enough – winter is approaching in the southern hemisphere.

We’re completely alone out here on the north end of Amanu. There is some evidence that humans have visited: a firepit, a mat woven out of palm fronds, a nail in a tree, but I don’t think they frequent the chain of motus near our anchorage. Farther south and farther north there are some very large motus, rich with coconut groves, which are actively being harvested for copra. But those zones are too far for us to see any activity. Copra (the raw material for making coconut oil) is a subsidized crop here. The subsidy helps keep people gainfully employed in their communities, and helps keep supply ships visiting. These bigger boats would not stop to drop off a few cases of corned beef and rice – but the shipping subsidy on copra makes it worth their while to visit some of these remote spots once a month. And the harvesting subsidy helps the families buy more of the supplies the ships bring. Pearl farming is also a big industry here, but not one that every family can afford in terms of startup expenses (and all are not equally skilled for the task), and with the world economy down, markets in luxury goods like pearls have probably suffered. From what I understand, pearl farming spiked a few years back with as many as 50 farms on some atolls, but things have settled back to a small handfull of farms at each atoll.

We’ll probably be here for another week or so, then we may try one other atoll before heading to the Australes. Frank and I have both visited other atolls in the Tuamotus, and they are stunning, but surprisingly similar. “You’ve seen one, you’ve seen ‘em all.” would be an exaggeration, but given the challenges of their passes, and the challenges once inside to moving around between coral heads, we decided that we’d pick one or two atolls to visit, hold still for awhile, and relish the moment. We are back into incredibly photogenic territory. When I asked Logan what he thought of all that we’re seeing here, he said, “I’m over-awed.”

We’re surrounded by a classic deserted tropical island view. Aqua waters, colorful reefs, sharks patrolling the reef edges, bright green motus, coral sandy inner beaches, rough coral gray outer zones. The ocean side of a motu has a surprising lunar landscape aspect. Big swells and storms have broken off huge hunks of outer reef, carried them across a wide reef shelf and deposited them in a giant coral graveyard inward halfway towards the lagoon. This wide swath of gray is the backdrop and structural base to each motu. Somehow verdant green “miki miki” sets root in this hostile salty stuff; the growing roots break up the coral blocks and catch smaller bits of coral and coral sand. The wind, rain, and waves keep depositing and packing material around these roots, building up terrain to an elevation that will keep roots high enough out of the salt water to sustain the life of a coconut tree. The motus of all sizes are separated by shallow channels where currents flow from the outside into the lagoon and back as the tides turn. The common explanation of an atoll is that reefs grew around an old volcano island, then the island sank, and the reefs kept growing. But Frank said he thinks it’s the sea level that rose over time, not the volcano that sank. The sea base in this zone is pretty constant, so it seems odd that islands would sink, without the whole zone sinking at the same rate. ‘Course I suppose that whether the land mass moves down or the sea moves up the result is submersion, and if submersion equals sinking, then we may be splitting hairs. One big storm can wash an entire motu off it’s reef, but the coral keeps growing, breaking, building in a continuous cycle. A few feet of raising sea-level would (will?) annihilate these atolls. Apparently they have found submerged “underwater” atolls called “Guyot.” These show all the evidence of once having been functioning atolls. Paumotu (people of the Tuamotus) have a tenuous existence on this planet. Frank met a guy once who, with his dad, rode out a storm on Motu Tunga by tying their little boat to a rock. Other villagers were tying themselves to coconut trees, but the entire village – trees and all were swept away. Only the guy and his dad survived from that village. Global warming is just one threat, among many each year, to these rugged folks. Hmmm, Frank just handed me a book with French nautical instructions which gives a detailed accounting of the geology of this area in the intro. I better go read it so I don’t miseducate all of you with my secondhand “Frank-said” info.

xoxomo