LAUSR

Submerged macrophytes constitute an important component of shallow aquatic ecosystems. They provide most of the accessible surface area, constant survival substrates, and available nutrients for periphyton, which remains attached to the stem and leaf surfaces of submerged macrophytes and forms a special bio⁃water boundary layer. As one of the most important interfaces in shallow lakes, the submerged macrophyte⁃water boundary layer plays roles in macrophyte growth, biogeochemical cycling, water environment maintenance, and ecological regulation. The present study summarizes the research advancements regarding characteristics of the micro⁃boundary layer (MBL) around leaves and stems of submerged macrophytes. The ecological functions, biotic and environmental factors, and research methods are identified and reviewed. Perspectives for the focus of future research on MBL around submerged macrophytes are raised.The MBL around submerged macrophytes has important ecological functions. The dense periphyton in MBL exerts negative effects on photosynthesis in submerged macrophytes, creates a barrier hindering the transport of dissolved substances, such as O2, and leads to the degradation and even disappearance of submerged macrophytes in eutrophic waters. The plant stress derived from pollutants may be alleviated because of the periphytic barrier in the MBL. The epiphytic bacteria in the MBL can be of considerable