Elizabeth Everett

Microplastics as a Disturbance to Food Web Dynamics in Texas Gulf Coastal Bays

Studies have improved our understanding of how aquatic organisms’ uptake microplastics (MPs), but there is a lack of information on their transfer through the food chain. To address this gap, a study combining field observations and lab experiments on ingestion is needed. This research will focus on the impact of MPs in the marine food web of Matagorda Bay in the Gulf of Mexico. By studying the abundance, composition, and distribution of MPs in this ecosystem and conducting feeding experiments on a two-level trophic chain from copepod to jellyfish, critical information on microplastic retention and its effects on fecundity, behavior, and growth will be provided. Copepods will be sampled in situ and examined for the microplastic body burden. MPs obtained from the field will be used in the lab-feeding experiments with copepod nauplii and jellyfish ephyra. It is expected that the consumption of MP contaminated copepods will negatively impact jellyfish development, with reduced pulse-per-minute rates and survival indicating physiological stress. Additionally, MP-fed copepods are likely to experience reduced growth, reproductive output, or impaired physiological functions. Initial findings revealed MP concentrations ranging from 1,591 to 15,275 MPs per liter across the 7 sampled bays. The three highest MP/L concentrations were observed in bays influenced by freshwater input. The initial analysis demonstrated that adult copepods exhibit a higher MP body burden compared to nauplii stages. Adult copepods average 4.0 MPs per individual, while nauplii average 1.7 MPs per individual. Additionally, the copepods from sites with freshwater input recorded the highest MP body burden. This data will inform future policies to reduce microplastic pollution in the marine environment and protect aquatic resources.