Undergraduate Research
How are humans indirectly impacting marine communities?
How are humans indirectly impacting marine communities?
While working in the Levitan Lab, I completed a Direct Individual Study (DIS) with Dr. Don Levitan and Kevin Olsen. I investigated the influence of microplastics on broadcast spawners, specifically examining the impact of these microplastics on fertilization success and sperm availability. I presented this work orally at Princeton EEB Scholar's Weekend and as a (very text heavy) poster at the Ecological Society of America's Virtual Conference in 2020.
The Influence of Microplastics on Fertilization Success and Sperm
Availability in Broadcast Spawners
Availability in Broadcast Spawners
Since its inception, plastic production has dramatically increased and become fully integrated into modern society. From 1950 to 2015, the world produced 6.3 billion tons of plastic, in which 79% was either put into the environment or a landfill. This plastic remains in the environment and slowly breaks down into small, fragmented particles known as microplastics. Through the additive effect of urban regions and constant urban development, water drainage systems collect large amounts of microplastics and channel them into surrounding aquatic watersheds, such as streams, lakes, and gulfs. Here, they can affect filter feeders, fish, and many organisms. These microplastics can affect an organism's physiology, behavior, and life-span. But how does it affect an individual's (specifically those that use broadcast spawning to reproduce) ability to recruit the next generation via fertilization? Fertilization is a key in recruitment and a significant decrease in fertilization, especially following large disturbances, may lead to demographic bottleneck. For my DIS, I investigated the influence microplastics on fertilization success and sperm availability in purple sea urchins (Arbacia punctulata). I hypothesized that microplastics would lower fertilization success by depleting sperm. I found that microplastics, even at varying sperm concentrations, have a clear negative effect on fertilization success. However, despite the significant effect of plastics on fertilization, low fertilization success within treatments could not be explained by sperm depletion. This inferred that instead, plastics are interfering with gamete interactions or effecting the performance of sperm/eggs. My study suggest that ecologically relevant concentrations of microplastics severely diminish fertilization success in A. punctulata by interfering with gamete performance, demonstrating that anthropogenic plastic pollution can impair and lower the reproductive fitness of commercially important spawning species. These are preliminary results.
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Why This Matters:
With an expected intensification of the hydrological cycle, the amount of runoff from urban areas will most likely increase. Therefore, due to the growing amount of plastic pollution that could end up in this runoff, understanding the effect of microplastics on aquatic ecosystems is crucial. The amount of plastic known to be in the ocean currently is most likely a gross underestimate due to ocean currents constantly moving small pieces of plastic, lack of knowledge about the deep sea, and microplastics becoming embedded in the seafloor. As the global population continues to grow and concentrate in urban areas, the contaminants and pollutants found in the watersheds surrounding urban areas will continue to rise without appropriate conservation policies in place to protect marine wildlife. Although microplastics are now receiving more attention in conservation ecology, the long-term effect that microplastic contamination has on the physiological and social aspects of different organisms within larger marine communities is still not fully understood. By investigating and understanding how these areas are connected, researchers will be able to provide policy makers with accurate and relevant information to assist in conservation planning.
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