Thursday, March 22, 2012

Brazil: Getting started at the Abrolhos Shelf

Les Kaufman, New England Aquarium research scholar, is in Brazil to study the unique marine habitats of the Abrolhos Shelf. He and fellow researchers intend to learn more about the marine life of Abrolhos, its links with terrestrial communities, how both are likely to be affected by global climate change and what people can do to protect this special place and oceans worldwide.

After a blessedly uneventful flight to Miami, and then Salvador, and finally Porto Segoro,
we drove the landward side of our study area, the Discovery Coast. This region was discovered by Pedro Alvarez Cabral in 1500, only about two thousand years after it was first discovered by the people who actually lived there.

A shipwrecked anchor monument in Porto Seguro, we are in search of its story.

It is a landscape once carpeted by majestic Atlantic rainforest, replaced today by cattle ranches and eucalyptus plantations.

Eucalyptus plantation on the road from Porto Seguro to Caravelas

It is also a place of vast lowland habitats called restinga, a mix of dunes, mangroves, scrub, forest, wetlands and people expert at putting together a living in this challenging but stunningly beautiful ecological landscape.

The vegetation of the restinga is a strange mix of strange elements — including perhaps the strangest — riverine wetlands dominated by bromeliads, relatives of the pineapple. We are here to study the Abrolhos Shelf, and I look forward to joining my Brazilian colleagues both on land and at sea. Our goal is to learn more about the marine life of Abrolhos, its links with terrestrial communities, how both are likely to be affected by global climate change and what people can do to limit the bad and max out the good in this most unwelcome stepchild of our own explosive growth in numbers, affluence, and technology.

Restinga-wetland ecotone, with marsh bromeliads visible in the foreground, cows way in back

Abrolhos is a large region in the southern region of northern Brazil, well south of the Amazon River mouth. This roughly circular ledge of continental shelf projects out about 120 miles to the east of the scenic beaches of Bahia. It is a magnet for whalewatchers, divers, sport fishermen and vacationers, and home to the lion’s share of the coral reefs in all the south Atlantic ocean. The Brazilian marine team, consisting of scientists from several local universities and Conservation International, has made astonishing discoveries out here, many assisted by a side scan sonar survey conducted a couple of years ago. In this expedition, we are exploring exciting, little-known marine habitats in several ways: with normal SCUBA diving (down to about 120 feet maximum), with deeper technical diving that uses special mixed gasses (to about 250 feet), with a special video camera on a cable (with another, high-definition video camera perched on top of that one), and with an ROV or “remote operated vehicle”, a sort of robot video on a cable that can be steered around under water.

View Larger Map

But habitats are more exciting than the technology.  First, of course, are the newly discovered deep reefs. Among these reefs we discovered vast fields of something called a rhodolith — a ball made out of layer upon layer of red algae that lay down a hard skeleton, something like that of coral. Each is about the size of a softball, and can be anywhere from around 300 to 8000 years old. These algae balls are piled 8000 years deep, and the ones on the top and sides are still alive. The Abrolhos rhodoliths could be one of the world’s largest stores of what we call “blue carbon”, or carbon kept out of the atmosphere, so it does not contribute to global climate change. 

The third new habitat is called a buraca — basically a vertical a hole or shaft going straight down into the shelf. There are lots of these holes, and we want to know more about them, because one of the things we’ve found inside them are big schools of young fish. This was a big deal: These are the young of commercially important species such as snappers, and previously we had only the vaguest idea where all the baby fish were coming from — certainly not the stork. The buracas may also give us greater access to the history of the shelf, in layers, along their exposed walls.  

The expedition is in legs, each a few days long, with teams swapping in and out as the mother ship, the Horizonte Aberto, tends station with the overlap team offshore. 

Last night we had a lovely dinner of endemic drum fish and peas below a powerfully full moon, land-crabbers moving systematically up and down the beach in search of their quarry, one with a horse-drawn cart. The children wheeled and played in lunar luminescence to the lulling sound of lapping wavelets. We talked about fish, and birds, and whales deep into the night.

Les is also working with Conservation International during this expedition. His entries are cross posted on their blog

1 comment:

  1. Blue carbon--who knew! Can't wait to hear what you find! Thanks for doing this important work.