Bones in dark underwater caves stayed pristine while light left algae marks

Animal bones resting on the floors of South Australia's underwater caves are revealing far more than the identity of the creatures they once belonged to. According to a new study published in PLOS One, the cave environment itself leaves distinct "fingerprints" on bones, helping scientists reconstruct how they were deposited, the environmental conditions they experienced after deposition, and the processes that affected their preservation over time. Researchers found that bones located near cave entrances, where sunlight penetrates the water, bore traces left by algae and other aquatic organisms, while bones from the caves' permanently dark zones remained exceptionally well preserved with minimal evidence of biological alteration.