Fishermen in Chetumal Bay, in the south of the Yucatan Peninsula (between Mexico and Belize),
have known about its existence for decades
and some scientists had carried out preliminary studies.
However,
it was not until September 2021
that the first immersions of divers and detailed analyzes with echo sounders, conductivity, temperature and depth profilers were carried out;
and images were taken of the interior of the blue hole known as
Taam ja'
(deep water, in the Mayan language).
The results of this first large study, which were published in the specialized journal Frontiers Marine Sciences, indicate that the Taam ja'
reaches 274.4 meters below sea level
, thus becoming "the second deepest known blue hole in the world".
The hole
has an almost circular shape on its surface
, covering an area of approximately 13,690 m2.
The sides of the blue hole are nearly vertical (>80°) and form a large conical structure covered by biofilm, sediment, limestone, and gypsum ledges.
The first images of the interior of the second deepest blue hole.
Meanwhile, the mouth of the blue hole is located between 4.5 and 5 meters below sea level, so
the properties of surface water change
significantly with the tides.
The water column inside this blue hole
also shows great variations
in conditions such as oxygen concentration, chemistry, temperature, and biological formations.
The first images of the interior of the second deepest blue hole.
The researchers analyzed the changes in the water at different depths and reported hydrographic profiles that show
a stratified water column
inside the blue hole consisting of several layers: the first very low oxygen or hypoxic layer is located between 5 and 20 meters below. the sea level.
The first images of the interior of the second deepest blue hole.
Then, there is the second layer called the chemocline, where water masses with different salinity and oxygen properties
are found
, and it is located between 50 meters and 80 meters below sea level.
Taam ja' - The second deepest Blue Hole in the world
And finally, below 110 meters below sea level is the last layer where
dissolved oxygen is depleted
and is called the anoxic layer.
scientific knowledge
The team that authored the study, led by Juan C. Alcérreca-Huerta (researcher at the National Council of Science and Technology-El Colegio de la Frontera Sur de México), explained that coastal karstic formations (blue holes) have been little
explored by the global marine scientific research community.
The first images of the interior of the second deepest blue hole.
This was one of the reasons why they decided to start this project.
The first images of the interior of the second deepest blue hole.
Data from fishermen and superficial scientific studies encouraged this team to "
explore the geomorphometric
and physicochemical characteristics of a submerged blue hole in the large tropical estuary of Chetumal Bay, off the southeast coast of the Yucatan Peninsula, Mexico."
Source: The Vanguard
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