Food demand is predicted to increase by 50 percent by 2050 as the global population approaches 10 billion, emphasizing the urgent need to improve the productivity. Agriculture is essential for the global economy and food security but is also a major contributor to environmental degradation, particularly through freshwater contamination. The present study explores the socio-economic factors driving the intensification of agricultural activities, including the widespread use of fertilizers and pesticides, and examines their cascading effects on marine ecosystems. Using a secondary research methodology that synthesizes peer-reviewed studies, government reports, and policy documents, the review analyzes the causes, ecological and economic implications, and mitigation strategies of agricultural runoff. By linking agricultural development with nutrient runoff and its impact on marine biogeochemical cycles, the study provides insights into how human economic activities shape environmental processes. The findings highlight the dual challenge of supporting agricultural productivity while safeguarding coastal ecosystems, emphasizing the need for sustainable policies and practices to balance economic growth and environmental conservation.