A metabolic approach to assessing interactions between climate change, agrochemicals, and freshwater mussel reproduction

Abstract

Unionid mussels are a fundamental part of stream ecology yet are one of the most threatened aquatic organisms due in part to habitat loss, stream fragmentation, and deterioration. The increasingly relevant effects of climate change will further threaten freshwater mussel populations by not only causing a rise in temperature within streams, but by also causing an influx of sedimentation and agrochemicals entering streams due to more strong rainfall events. Due to the unique strategy unionid mussels use to reproduce, assessing the effects of temperature and common agrochemicals have on gravid mussels’ metabolic rates and glochidial retention is a necessary step in developing better management practices. To do this, we estimated premature brood expulsion and metabolic stress through the use of closed respirometry by examining the effects of: 1) increasing temperatures and declining dissolved oxygen levels 2) exposed gravid mussels to three common agrochemicals over a 28-day period. Results suggested that temperature, dissolved oxygen levels, and certain agrochemicals affected gravid mussels’ metabolic rates as well as their ability to retain glochidia.