Mangroves on the Yucatan

8 Oct 2021

At https://phys.org/news/2021-10-hidden-mangrove-forest-yucatan-peninsula.html ... this story is all about the vagaries of computer modeling and how conclusions can be reached by not factoring in all the evidence. They may be right - and they may be wrong. I don't know. Deep in the heart of the Yucatan Peninsula, there is an ancient mangrove forest 124 miles from the nearest ocean. Mangroves are salt tolerant trees and shrubs that usually flourish along tropical and sub tropical coastlines. A team of researchers from the US and Mexico set out to discover how they might have come to be growing so deep inland in what is a freshwater habitat - along the banks of a river. They reverted to sea level modeling as it is likely the mangroves, at some point in time, were growing on a coastline. A reasonable deduction. They, therefore, used the mainstream sea level curve in conjunction with various other data [biological for example as a variety of plants grew in the forest] and geology etc. Up pops out of their computer the answer. They have been growing along the river since the last interglacial - 120,000 years or more ago. The mangroves, they say, have persisted there even during the last glaciation. At the time, the world was much warmer. Well, it was, at least in some locations. We are told as a result of the warmth sea levels were 20 to 30 feet higher than the present  - high enough to flood the Tabasco lowlands of Mexico and drown tropical rainforest. All of it is guesswork and assumption. Nobody has any idea what sea levels were like globally 120,000 years ago. They may know what they were in a specific location, but not around the world. No research has been done on a global basis. The same goes for sea levels at the end of the Ice Age. They know they have risen in the North Atlantic - but what about in other parts of the world. The same goes for the massive sea level changes that occurred 8000 years ago. Some regions of the world were drowned but others seem to have gone down - at the same point in time. Take Lake Titicaca on the high altiplano. In the last Ice Age, it was a tidal lagoon at sea level. It was subsequently left stranded, far from the sea, and continued to be elevated, at other points in time during the Holocene. The research is the product of computer simulation. It is therefore a hypothesis that may or may not be valid. See https://doi.org/10.1073/pnas.2024518118