From the ACS Press Room Decreased Iron Levels in Seawater Make Mussels Loosen Their Grip “Availability of Environmental Iron Influ- grew the mussels in each water condition for ences the Performance of Biological Adhe- three days, during which the creatures atsives Produced by Blue Mussels” tached to aluminum plates. Then, the reEnvironmental Science & Technology searchers cut off the threads near the shell Mussels secrete sticky plaques that help them and pulled upward on them, measuring the attach to wet surfaces, such as rocks on the force beach. These adhesive structures are rich in needed iron, which is thought to help make the at- to retachments strong yet flexible. Now, research- move ers reporting in Environmental Science & the Technology have shown that mussels form plaque weaker attachments in iron-deficient sea- from water, revealing a possible consequence of the plate. altered iron bioavailability in oceans. As the concentration of iron in the water inAs oceans become more acidic in a changing creased, so did the plaque’s stickiness, exclimate, iron dissolves and is less bioavaila- cept for the highest iron level, at which adheble to filter feeders, such as mussels, that sion slightly decreased. The team also obstrain iron particles from seawater. In mus- served that the plaques became smaller and sels, iron helps cross-link proteins in the darker as the iron concentration increased, sticky plaques that attach to surfaces and and the porous microstructure of the plaques adds mechanical toughness to the hair-like became more pronounced. This study is the threads that link the plaque to the mollusk’s first to examine how changing iron levels afinner tissues. Jonathan Wilker and colleagues fect the performance of a biological material at Purdue University wondered how mussels’ in a whole animal, the researchers say. ability to adhere to surfaces would be affectThe authors acknowledge funding from ed by changing iron levels in seawater. the Office of Naval Research, the National To find out, the researchers cultured mussels Science Foundation and the Purdue Research in artificial seawater containing lower, nor- Foundation. mal and higher iron levels. The researchers September 2020
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