Research
Research comes in various categories and includes, the study of cave fauna, Microbiology and Geochemistry, water contamination, Hydrology and Geology.
Flooded caves are geological time capsules where fossil remains and archeological artifact remain frozen in time and perfectly preserved.
Archeological investigation and Paleontological discoveries are
commonplace here.
PROJECT ANTILLOTHRIX,
FOSSILS OF HISPANIOLA'S FLOODED CAVES.
Alfred L. Rosenberger, PhD
Professor. Department of Anthropology and Archaeology
Brooklyn College, CUNY
Typically, the only large animals you’ll see today in the Dominican Republic countryside are domesticated, pet dogs, and the goats, cows and horses providing food and working on farms – all brought in by Europeans in the last few hundred years. Step back in time a couple thousand years, and a walk through the more forested landscape that existed then, or along rivers, lagoons and beaches, and a very different picture comes to mind. It’s an image that has been made real through discovering the fossils of extinct animals found in flooded caves. There were 200 lb. giant ground sloths roaming about, monkeys moving through the treetops, a rodent called the twisted-toothed giant Hutia and others no longer living, a Cuban crocodile, and more. They were all descendants of animals that managed to cross from the South American mainland or from other Caribbean islands, in some cases millions of years ago. And they all became extinct over a brief period of time after people arrived in Hispaniola not much more than 5000 years ago.
The flooded caves of the Dominican Republic are a rich source of fossils, some more than a million years old. Exactly how these caves accumulated their remains is a question that will require a lot of research to answer. But one thing is clear. The fossils tend to be exceptionally well preserved, although in some places they are so thickly crusted by dripstone, the same mineral material that forms stalagmites and stalactites, as to be almost unrecognizable. For paleontologists, there is no place better to find fossils because the layered sediments that normally bury bones and begin the petrification process in other parts of the world are extremely rare in the DR. Flooded cave paleontology is fast becoming one of the best potential sources for discovering how and when the native fauna of Hispaniola went extinct, whether it was the impact of humans occupying and using the land, or climate change, or perhaps a combination of factors. It is a new way of discovering the past, and one of the scientific exploratory objectives of the DRSS.
For several years, DRSS has partnered with the Museo del Hombre Dominicano and Brooklyn College to explore flooded caves in search of primates, mostly, and other vertebrate fossils. Our aim is to assemble a collection of fossils that will help reconstruct the evolutionary history of mammals that occupied Hispaniola in the remote past, and tie that in to the fossil record coming from the rest of the Greater Antilles, from Puerto Rico, Jamaica and Cuba. So far we have found examples of all of the groups of mammals that are known to be Dominican or Hispaniola natives, now and in the past. We have found the remains of 25 mammal species. At least 11 of the species are extinct, and 13 of them are unique to the Greater Antilles. The monkeys are represented by Antillothrix bernensis, which was the first New World primate ever found in the Caribbean, although it took many years before anyone realized that since it was so unexpected. Our studies of Antillothrix suggest it came to the Caribbean many millions of years ago, possibly before the primates that populate Amazonia evolved into an established ecological community, and one of the most successful mammal groups in South America.
The most abundant species we find are bats, which is to be expected because they are a very prolific order of mammals and they also tend to roost in caves. Second are the rodents. A recent new fossil addition to the group is the first skull ever found of the largest Caribbean rodent, Quemisia gravis, the giant hutia mentioned above. The giant ground sloths, several different genera, are commonly found as well. They were the largest native mammals and they were abundant, so their chances of being discovered are relatively good. The most surprising find has been one vertebra of a dolphin, the only marine mammal we have discovered so far. How it became mixed up in a deposit of terrestrial mammals is still a mystery. We have also found a few specimens of the rare solenodon, which is still alive on the island in small populations. The burrowing solenodons may be the oldest mammal, geologically, to have inhabited the Caribbean. Their roots may go back to the Age of Dinosaurs, but how and when they arrived is an unanswered question. Aside from these mammals, we have also found remarkably complete specimens of exotic crocodiles, a complete turtle, snakes, and birds, including a large predatory raptor that also lived in the United States but is now everywhere extinct.
The work continues. There will be more.
MICROBIOLOGY & GEOCHEMISTRY RESEARCH
By Jenn Macalady.
Underwater caves are windows into a hidden world that is partly or totally shielded from oxygen in the earth's atmosphere. In low-oxygen or oxygen-free cave waters, native microoganisms are more similar to the life that inhabited the earth's oceans billions of years ago than microbial life found in the oceans today. That makes underwater caves interesting to scientists who want to understand how biogeochemical cycles worked on the ancient earth (or even on hypothetical oxygen-poor extraterrestrial planets).
The water chemistry of each underwater cave reflects the geometry of its passages (its plumbing), the geology of the host rock, the sources of the water, and the amount of nutrients that enter by soil percolation or through skylights to the surface. Caves that are separated by only a mile over land may have radically different chemistry and microorganisms. This variety, plus the possibility of discovering something new about ancient microbial life, make underwater caves exciting and important places to study microbiology.
This figure shows the tree of life based on DNA sequences coding for the taxonomic marker gene called 16S rRNA. Life is organised into three domains (Eucarya, Archaea, and Bacteria). Organisms on branches covered by blue can be seen with the naked eye, and include animals, plants, and fungi. The rest of the of the branches represent diverse types of microorganisms.
Cave water microbiology and chemistry also give important clues about the movement of water below the ground surface. Understanding how water moves underground can help us predict the movement of nutrients and pollutants, an important part of safeguarding drinking water resources and natural habitats.
