Pollen preservation: Experimental wet‐dry cycles in saline and desalinated sediments

Experimental degradation of pollen by repeated wet‐dry cycles in saline and desalinated sediments show differences in preservation between taxa and between salinity environments. In desalinated sediment, from which the salts were removed artificially, pollen is rapidly degraded, with a significant net loss of pollen after ten wet‐dry cycles. Picea pollen, which remains identifiable even when heavily damaged, suffers greater breakage in desalinated sediments. Artemisia pollen is rapidly rendered unidentifiable by degradation of the sculptural elements in both saline and desalinated sediments. In comparison to desalinated sediments, saline sediments appear to contain less damaged pollen. Growing salt crystals may envelop the pollen grains and stabilize them against mechanical breakage otherwise incurred by flexing of the pollen wall during desiccation. Caution should be exercised when analyzing sediments subject to wet‐dry cycles, and laboratory procedures modified if necessary to avoid desiccation of pollen during processing.