We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Daphnia magna digestive activity is differentially altered when exposed to equally turbid waters caused by either suspended sediment or suspended microplastics
Summary
When tiny water fleas (Daphnia magna) were exposed to microplastics at the same concentration as natural sediment, they couldn't pass the plastic particles through their digestive systems as efficiently, reducing their feeding effectiveness. Unlike natural sediment, which the animals processed normally, microplastics disrupted gut motility in a way that suggests these filter feeders are poorly adapted to plastic pollution. This matters because Daphnia are a critical link in aquatic food chains, and impaired feeding could ripple up to fish and other predators.
Turbidity can be a result of suspended natural particles, such as sediment, or anthropogenic particles such as microplastics. This study assessed whether Daphnia magna, a pelagic filter feeder known to ingest suspended particles, have an altered response to equally turbid environments caused by the presence of either suspended bentonite or suspended polyethylene microplastics. Compared to controls, daphnids exposed to suspended bentonite maintained their feeding efficiency and increased their digestive activity, as measured by mandibular movement, peristalsis, and expulsion, to pass bentonite through the digestive tract. The same effects were not seen in microplastic-exposed individuals, in which feeding efficiency was decreased and only peristaltic movement was increased but without a coordinated increase in expulsion, suggesting that microplastics do not have the same ability as bentonite to pass through the digestive tract. This study highlights the need to discern the identities of particulates contributing to turbid environments as different particles, even of the same size, can have different effects on filter feeders, which inherently ingest suspended particles.