Subaqueous soil
Subaqueous soil material is found in two contrasting scenarios.1. Subtidal permanently saturated soil material bordering intertidal flats or other coastal features adjacent to MLWS (e.g. beaches, dunes, headlands). See Subtidal soil, and
2. Inland water bodies that are only rarely exposed in extreme droughts (at the most one year in 9 on average).
The height of the water body may fluctuate but essentially always covers the saturated subaqueous soil material. The water may be fresh or saline.
An example of investigating subaqueous soil is presented in this link.Scroll to pages 10 and 11 and note figures showing a demonstration of sampling for Subaqueous soil.
The soil below exists beneath extremely clear water and also shows large cracks. This suggests this water body at some stage has been lowered for a significant period and the soil has dried out. Consequently, it is not likely to be a subaqueous soil that stays saturated for more than 1 year in 9.
Furthermore the extreme clarity of the water suggests that it may be acidic and aluminium rich, leading to flocculation of any suspended sediment. This is commonly seen in drained soils containing hypersulfidic material.
Soil material under water may or may not qualify as a Subaqueous soil. Seek local knowledge to confirm classification.
Photo credit: Bernie Powell
This core shows the black and dark gley colours commonly found in subaqeous soils forming under reducing conditions.
Photo credit: Luke Mosley, University of Adelaide