Zooplankton responses to environmentally relevant microplastic conditions at low food availability

The escalating global problem of aquatic pollution from plastic waste, particularly microplastics, demands attention to understand its impact on different trophic levels and how it moves through aquatic food webs. Microplastics, which come from fragmented degraded plastics such as water bottles, can take hundreds of years to decompose. Current literature on the impacts of microplastics on aquatic organisms often lacks real-world relevance because of unrealistic plastic types and concentrations. This study investigates the effects of environmentally relevant microplastic exposure on the life history characteristics and ingestion of Daphnia magna and Daphnia pulex using different plastic shapes, sizes, types, and concentrations at low algal food concentrations. We also followed organisms throughout their entire life cycle to capture potential long-term impacts of microplastic exposure that may be missed in shorter studies. We hypothesized that exposure to relevant microplastic conditions would negatively affect zooplankton. While initial early life stages may not be affected, higher concentrations and denser plastics (Polyvinyl chloride) are expected to cause reduced reproduction, shortened lifespan, reduced growth, and increased plastic ingestion. Conversely, lower concentrations and lighter plastics (Polypropylene, Polystyrene) may not impact life history due to lower particle exposure and ease of filtering the lighter plastics. Despite these predictions, we found that microplastic exposure at environmentally relevant conditions had little impact on D. magna life history regardless of concentration and plastic type. Microplastics can accumulate in Daphnia and may have negative impacts as they move up the food chain.

Primary Presenter: Mitchell Nagel, Oklahoma State University (minagel@okstate.edu)

Authors:

Mitchell Nagel, Oklahoma State University  (Minagel@okstate.edu)

Andrew Dzialowski, Oklahoma State University  (andy.dzialowski@okstate.edu)

Jorge Gonzalez-Estrella, Oklahoma State University  (jorgego@okstate.edu)

Rui Cai, Oklahoma State University  (rui.cai@okstate.edu)

Avin Todora, Oklahoma State University  (atodora@okstate.edu)