Metal Accumulation in the Shell and Soft Tissues of Non-native Mysterysnails

Abstract:

Non-native species threaten native habitats by outcompeting native species, disrupting food chains, and reducing biodiversity. Non-native mysterysnails were introduced to the Great Lakes region due to the pet trade and shipping activities. In addition to the classic adverse effects of non-native species, mysterysnails also accumulate toxic metals that can affect native ecosystems. As a self-preservation mechanism, snails have been known to transfer acquired metals into their shells away from essential organs. However, the relative allocation of metals to shells versus various soft tissues in mysterysnails is unknown. Therefore, this study aims to determine how metal concentrations differ between the shell and soft tissues of mysterysnails. To determine the distribution of metals within these snails, we collected snails, water, and sediment samples at documented invasion sites – Presque Isle, Pymatuning Reservoir, Lake Arthur, Lake Canadohta, Edinboro Lake, and Lake Pleasant – in Summer 2022. Lab work consisted of dissecting snails to separate the shell and internal organs (gonad, mantle, foot, gut) and quantifying metal concentrations in water, sediment, and tissue samples. We found that metal accumulation varied by tissue type, with relatively little accumulation of metals in mysterysnail shells. Copper had the highest partitioning from sediment, with the greatest accumulation in the gut. Considering the sensitivity of many snail species to copper, it is possible that copper accumulation could be affecting the physiology of non-native mysterysnails in Pennsylvania. Understanding the concentration of metals in the different tissues of mysterysnails will help us understand how their physiology influences their ability to respond to contamination and what additional threats they may pose to native species. This information can aid in developing management plans for mysterysnails in the Great Lakes region.