| Depositional conditions early post-mortem influence net shell alteration prior to fossilization. This study assesses the progressive degradation of experimentally deployed Mytilus edulis shells and natural aragonite crystals during 13 months at and 10--20 cm below the sediment surface in High- and Mid-Marsh Salt Marsh Ponds, a Beach and a Cove (Bay of Fundy, NB, Canada). Changes in net weight, macroscopic, and microstructural features are examined in the context of environmental conditions. Results show that: (1) early degradation processes act very quickly, causing significant changes in shell condition within 13 months post-deposition. (2) The sloughing off of shell crystallites loosened by maceration, bioerosion and maceration, in order of importance, dominate shell degradation in the study environments. (3) Dissolution contributes relatively little to the overall taphonomic signature during early shell degradation. |
