Today: Monday, 22 April 2024 year

Archaeology: Seagrass meadows as an underwater time capsule

Archaeology: Seagrass meadows as an underwater time capsule

Archaeology should be extremely thankful for the seagrass, which creates a type of underwater time capsule that can encase and protect shipwrecks or Stone Age settlements, for thousands of years, Science Nordic reported.

The organic and chemical structure allows them to function as a keeper of underwater objects, many of them are rare, precious or even invaluable for the archaeology, says the article in journal Ambio. According to the senior researcher Dorte Krause-Jensen, the seagrass is removing carbon dioxide from the atmosphere, and protecting our coasts from sea level rise, and boosting biodiversity.

In terms of marine ecology, underwater meadows stabilise the seafloor by dampening wave energy and forming a stabilising network of roots and stems. The banal Laminaria or Zostera marina is able to create the seabed by capturing remains of seaweed and other particles in mat-like layers, burying deeper sediments and protecting anything buried within them as the seagrass continues to grow.

Seagrass meadows help to provide the right conditions needed to preserve archaeological treasures by locking out oxygen, which might otherwise promote degradation, say researchers from Aarhus University.

Historic archive in the seagrass

The gradual build-up of the seabed over the millennia provides insights into human activities throughout history. We can also use seagrass as a type of archive that we can dig in to and study the past.

Dates and chemical analyses of the thick deposits underneath seagrass Posidonia oceanica in the Mediterranean give us a glimpse of how soil was used in agriculture and metal extraction. Analyses of more recent deposits reveal a drop in lead content, associated with the transition to unleaded fuel.