Hydrogeologisella

Hydrogeologisella is a genus of radiolarian fossils that are found in sedimentary rocks, particularly in marine and lacustrine settings. The name Hydrogeologisella is derived from the Greek words "hydor" meaning water and "geologisella" meaning small geological one, indicating its fossilized presence within water deposit layers. These fossils are often discovered in sedimentary rocks that have been formed from the accumulation of sand-sized particles.

These fossils have been radiometrically dated to range from the Holocene to the Eocene epochs, spanning approximately 23 million years. The lipid composition of the cell walls of Hydrogeologisella is mainly made up of alkenones, which are macrocardie non-hydroxylated. The accepted main Group formula for this component is C36H64.

Research on these fossils has provided significant insights into the Earth's past climate. The presence of Hydrogeologisella in sediment cores suggests that these microorganisms once thrived in marine environments around Greenland, during the Eocene epoch 50 million years ago. Subsequently, it's been identified that many different sedimentary layers harbor abundant Hydrogeologisella population. During these epochs the climate is preserved within rock blocks undergoing contrasting geological events, which mainly provide facts on ocean oxygenation patterns over the period.

A yearly fluctuation of locally climate type inferred by an interdisciplinary group is tested yearly. Critically the study highlights acidification changes immediate if brink margin facing sediments.