Lost world gives glimpse of planet before last Ice Age

A lost world in Mexico has offered scientists a glimpse of the planet before the last Ice Age.

Scientists have identified a mangrove forest located on the San Pedro Martir River, which is the last remnant of an ancient ecosystem dating back 110,000 years ago.

- Advertisement -

A mangrove is a shrub or tree that grows in coastal saline or brackish water, first appearing during the Late Cretaceous to Paleocene epochs, and became widely distributed in part due to the movement of tectonic plates.

The San Pedro Martir mangrove forest was once on the shores of a vast ocean where the temperature was much warmer, but is now situated more than 170 kilometres inland due to climatic changes in sea levels. The forest offers a snapshot of the ancient past, allowing scientists to understand how environments adapted to changing sea levels as the global climate changed.

Dr Octavio Aburto-Oropeza told the Natural History Museum (London): “The most amazing part of this study is that we were able to examine a mangrove ecosystem that has been trapped in time for more than 100,000 years. There is certainly more to discover about how the many species in this ecosystem adapted throughout different environmental conditions over that time.”

In a paper published in PNAS by the University of California, the researchers took genetic and geological samples to work out exactly how the mangroves made it from the coast to the river.

- Advertisement -

Their study found that the San Pedro Martir mangroves are related to those found at the coastal Términos Lagoon in southern Mexico, becoming a divergent group separated during a period of history known as the Eemian or Last Interglacial.

At the time, the world temperature was three to five degrees °C warmer than present day, causing icesheets around the world to melt that resulted in sea levels rising by six to nine metres.

As the coastal regions of Mexico is relatively flat, the sea level changes submerged vast areas of land, with geological samples of aquatic shells and rounded pebbles indicating that much of the land was underwater during the Eemian.

At the time, far from being isolated from the sea, the mangroves of the San Pedro Martir River were once on the coastline of a large ocean. Following cooling temperatures as the last Ice Age began the sea levels declined, leaving the mangroves isolated in the river.


Header Image Credit : Dararat Insuwan – Shutterstock

- Advertisement -
Mark Milligan
Mark Milligan
Mark Milligan is multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 7,500 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.

Mobile Application


Related Articles

Archaeologists uncover 4,200-year-old “zombie grave”

Archaeologists from the State Office for Monument Preservation and Archaeology Saxony-Anhalt have uncovered a "zombie grave" during excavations near Oppin, Germany.

Archaeologists uncover 2,000-year-old clay token used by pilgrims

A clay token unearthed by the Temple Mount Sifting Project, is believed to have served pilgrims exchanging offerings during the Passover festival 2,000-years-ago.

Moon may have influenced Stonehenge construction

A study by a team of archaeoastronomers are investigating the possible connection of the moon in influencing the Stonehenge builders.

Archaeologists explore the resettlement history of the Iron-Age metropolis of Tel Hazor

Archaeologists are conducting a study of the Iron-Age metropolis of Tel Hazor to understand how one of the largest “megacities” of the Bronze Age was abandoned and then resettled.

Excavation uncovers possible traces of Villa Augustus at Somma Vesuviana

Archaeologists from the University of Tokyo have uncovered further evidence of the Villa of Augustus during excavations at Somma Vesuviana.

Study reveals new insights into wreck of royal flagship Gribshunden

Underwater archaeologists from Södertörn University, in collaboration with the CEMAS/Institute for Archaeology and Ancient Culture at Stockholm University, have conducted an investigation of the wreck of the royal flagship Gribshunden.

Microbe X-32 – Is the Plasticene Era coming to an end?

Breaking, a new venture in collaboration with Harvard and the Wyss Institute, is claiming that a new discovery, Microbe X-32, can naturally break down polyolefins, polyesters, and polyamides in just 22 months.

Stone sphere among artefacts repatriated to Costa Rica

395 pre-Columbian artefacts have been repatriated to Costa Rica thanks to a grant by the United States Embassy to the Cultural Agreements Fund.