生物地质化学循环（英语：Biogeochemical Cycle，又称作生态系统的物质循环）在生态学上指的是化学元素或分子在生态系统中划分的生物群落和无机环境之间相互循环的过程。这使得相关的元素得以循环，虽然实际上在某些循环中化学元素被长期积聚在同一个地方而不发生移动。（如海洋或湖泊的水）。

例如，水始终是通过水的循环回收利用，如该图所示。水经过蒸发，凝结和降水，干净清爽的回落到地球。通过生物化学循环，元素，化合物，以及其它形式的物质是从一个生物体到另一个生物体，并从生物圈中的一个部分到另一个部分。

In Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical substance moves through both biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) compartments of Earth. A cycle is a series of change which comes back to the starting point and which can be repeated. Water, for example, is always recycled through the water cycle, as shown in the diagram. The water undergoes evaporation, condensation, and precipitation, falling back to Earth. Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles.'