Inland water bodies such as lakes and estuaries are critical hotspots of carbon cycling, yet their contributions to the global carbon cycle are not fully understood. Muskegon Lake, a productive Great Lakes estuary at the terminus of Michigan’s third-largest watershed, is impacted by anthropogenic eutrophication, harmful algal blooms (HABs), and bottom water hypoxia. Seasonal metabolism measurements from 2004–2024 indicate that Muskegon Lake generally functions as a net carbon sink, with an overall annual state of autotrophy. Summer exhibits the lowest average production-to-respiration ratio (3.46) compared to spring (5.26) and fall (7.55), reflecting seasonal variations in carbon dynamics. Recent high-frequency measurements (2023–2024) reveal peak production in late May and early June, suggesting past seasonal measurements may have missed critical periods of heightened productivity. Complementary analyses of continuous high-frequency (sub-hourly) dissolved oxygen data from the Muskegon Lake Observatory (www.gvsu.edu/buoy/) are being analyzed to provide a more nuanced understanding of carbon dynamics. In 2024, nutrient analyses during an unusually prolonged HAB event revealed significant spatiotemporal variability. Nitrate (NO3) concentrations varied significantly by month (p=0.0225) and station (p=0.00135), while total phosphorus (TP) levels differed by month (p=8.26e-07), underscoring the role of environmental drivers such as precipitation, storms, and seasonal temperature shifts. These findings emphasize the importance of coupling nutrient data with metabolic and environmental measurements to better understand ecosystem processes. Muskegon Lake provides a model for studying how climate change impacts carbon dynamics in temperate estuaries. Long-term trends, such as El Niño and La Niña cycles, along with short-term episodic events like storms, contribute to variability in carbon flux. These insights are crucial for understanding how inland water bodies respond to and influence global climate change, particularly as warming temperatures, altered precipitation patterns, and extreme weather events become more frequent. Our study aims to better assess the role of estuarine systems in the global carbon cycle, particularly under changing climatic conditions.