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Are calcitic layers an effective adaptation against shell dissolution in the Bivalvia?
Author(s) -
Harper E. M.
Publication year - 2000
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.2000.tb00602.x
Subject(s) - calcite , aragonite , dissolution , shell (structure) , bivalvia , seawater , microstructure , materials science , mineralogy , biology , chemical engineering , mollusca , geology , ecology , metallurgy , composite material , engineering
Conventional wisdom, based on properties of reagent‐grade salts, states that organisms which construct their exoskeletons from calcite rather than aragonite have a greater ability to resist dissolution. However, experiments on individual bivalve microstructures show that other factors such as crystal size and the proportion of organic matrix outweigh constituent mineralogy in determining the rate of shell loss in cold waters. Moreover, the loss of shell material was minimal, corresponding to an annual loss in shell thickness of 3–40 μm depending on microstructure. These findings must cast doubt on the commonly held supposition that calcitic layers added to the outside of shells are an adaptation against dissolution in Holocene ‘Aragonite’ seawater.