Abstract

Aquatic ecosystems, including oceans, rivers, lakes, and wetlands, are central to the global biogeochemical cycles that influence climate change. These ecosystems play pivotal roles in regulating the Earth's climate by storing, cycling, and releasing greenhouse gases, such as carbon dioxide (CO2 ), methane (CH2 ), and nitrous oxide (N2 O), which directly affect the atmosphere's composition. The dynamic interactions within these aquatic environments, such as the absorption of carbon by marine phytoplankton, the release of methane from wetlands, and the impact of freshwater ecosystems on nutrient cycling, are integral to understanding their contribution to climate change. This paper explores how different aquatic ecosystems contribute to the global carbon and nutrient cycles, how human activities have altered these natural processes, and the potential consequences of these changes. Understanding the biogeochemistry of aquatic ecosystems is crucial for developing strategies to mitigate climate change, preserve biodiversity, and manage ecosystem services.