Microplastics (MPs) and nanoplastics (NPs) pose significant threats to aquatic and terrestrial ecosystems, disrupting nutrient cycling, altering soil properties, and affecting microbial communities. MPs and NPs bioaccumulate and contribute to global nutrient and water cycle disruptions, intensifying the impact of climate change. Despite the widespread use of plastics, inadequate plastic waste management leads to persistent environmental pollution. Toxic compounds are transported by MPs and NPs, affecting food chains, nutrient cycles, and overall ecosystem health. MPs impact soil biogeochemistry, microbial activity, and greenhouse gas emissions by altering the nitrogen and carbon cycles. One of the largest gaps in microplastic (MP) research today is the lack of standardized sampling and analytical methods. This lack of standardization significantly complicates the comparison of results across different studies. Multidisciplinary research and strict regulatory measures are needed to address MP pollution. This review highlights the critical need for mitigation methods to maintain ecosystem integrity and suggests standardization of sampling and data analysis. It offers insights into MP distribution, best practices for data analysis, and the impacts and interactions of MPs with biogeochemical processes. The Environmental Protection Agency has identified a critical need to improve the identification of nanoplastics. Particles smaller than 10 μm become increasingly difficult to quantify using standard MP detection practices.